TWI716633B - Method for inwardly reducing coloring area of colored 3d object - Google Patents

Abstract

A method of inwardly reducing a coloring area of a colored 3D object is disclosed and including: importing a 3D object; performing a slicing process on the 3D object for generating multiple object printing-records and multiple color printing-records corresponding to multiple printing layers; performing an inwardly-reducing process on a color printing-record corresponding to a lowest need-to-be-colored printing layer for generating an inwardly-reduced color printing-record; storing the multiple object printing-records, the multiple color printing-records and the inwardly-reduced coloring printing-record. When performing printing, a 3D printer controls a 3D nozzle to print slicing objects of the printing layers according to the object printing-records, controls a 2D nozzle to color one of the slicing objects corresponding to the lowest need-to-be-colored printing layer according to the inwardly-reduced color printing-record, and controls the 2D nozzle to color the rest slicing objects corresponding to the color printing-records.

Description

Method of shrinking colored area of colored 3D objects

The invention relates to a color 3D object, in particular to a method for shrinking a colored area of a color 3D object.

In view of the maturity of 3D printing technology, as well as the reduction in size and price of 3D printers, 3D printers have become popularized at an extremely fast speed in recent years. In order to make the printed 3D model more acceptable to users, some manufacturers have developed 3D printers that can print color 3D models.

Refer to Figure 1, which is a schematic diagram of a related art 3D printer. Fig. 1 discloses a 3D printer 1 with a printing platform 11, a 3D nozzle 12, and a 2D nozzle 13, wherein the 3D nozzle 12 and the 2D nozzle 13 are co-constructed on the same control rod 14 to be affected by the 3D printer 1 Joint control.

The 3D nozzle 12 is used for injecting molding materials to print a 3D model. The 2D nozzle 13 is used for spraying ink on the 3D model to color the 3D model. In this way, the 3D printer 1 can effectively print the above-mentioned color 3D model.

Refer to FIG. 2A and FIG. 2B, which are the first layer schematic diagram and the second layer schematic diagram of the related art 3D object, respectively. Depending on the content of the 3D object imported by the user, when the 3D printer 1 prints the 3D model 2 in color, it sometimes needs to color the bottom surface of the 3D model 2 (meaning that the entire bottom surface is colored, not just Coloring on the outer contour).

When the 3D printer 1 prints such a 3D model 2, it will first control the 3D nozzle 12 to spray the molding material on the printing platform 11 to print the first layer 21 of the sliced object of the 3D model 2, and then control the 2D The spray head 12 sprays ink on the first layer 21 of the sliced object to color the first layer 21 of the sliced object. After the coloring of the first layer 21 of the layered object is completed, the 3D printer 1 controls the 3D nozzle 12 to spray the molding material on the first layer 21 of the colored layered object to print the second layered object of the 3D model 2. Layer 22.

As shown in FIG. 2B, since the first layer 21 of the sliced object is covered with ink, the ink will weaken the adhesion of the molding material, resulting in the adhesion between the first layer 21 of the sliced object and the second layer 22 of the sliced object Decrease, and the problem of easy separation or warping occurs, which leads to the weakening of the overall structure of the 3D model 2.

Furthermore, the 3D printer 1 first sprays the molding material on the printing platform 11 to print the first layer 21 of the sliced object, and then color the first layer 21 of the sliced object, so the first layer of the sliced object The adhesion between 21 and the printing platform 11 is quite high. When the 3D model is printed and the user wants to remove the 3D model from the printing platform 11, the first layer 21 of the sliced object is attached to the printing platform 11 and separated from the second layer 22 of the sliced object. phenomenon.

As mentioned above, how to improve the structural strength of the color 3D model (especially the color 3D model whose bottom surface needs to be colored) is a technical problem that needs to be overcome in the technical field.

The present invention provides a method for shrinking the colored area of a color 3D object, which can shrink the colored area of the bottom surface of the 3D model, and increase the adhesion of the 3D model by expanding the uncolored area of the bottom surface.

In an embodiment of the present invention, the method for shrinking the colored area of the color 3D object includes the following steps: importing a 3D object; performing all layer processing on the 3D object to generate multiple printing layers of multi-stroke object printing Information and multi-color print information; perform an indentation process on the color print information of the minimum coloring print layer to generate indented color print information; store the multi-object print information and the multi-color print information Print information and print information in the indented color. When printing, a 3D printer controls a 3D print head to print the sliced objects of each print layer according to the multiple object print information, and controls a 2D print head to color the minimum required color according to the indented color print information The sliced object of the printing layer is colored, and the 2D nozzle is controlled to color the sliced object of other printing layers according to the multi-color printing information.

The various embodiments of the present invention can be applied to a 3D model whose bottom surface needs to be colored. Specifically, the present invention expands the uncolored area of the bottom surface by shrinking the colored area of the bottom surface of the 3D model, and increases the adhesion between multiple sliced objects by expanding the uncolored area, and then Improve the overall structural strength of the 3D model.

For a preferred embodiment of the present invention, with the drawings, the detailed description is as follows.

As mentioned above, the main purpose of the various embodiments of the present invention is that when the bottom surface of a 3D model needs to be colored, the color printing information of the bottom surface is first contracted to expand the uncolored area of the bottom surface object To improve the adhesion of the bottom object, and then improve the overall structural strength of the 3D model.

Refer to FIG. 3A, which is an indented flowchart of a specific embodiment of the present invention. FIG. 3A discloses a method of shrinking colored areas (hereinafter referred to as shrinking method) of the present invention, which is mainly applied to the 3D printer 1 shown in FIG. 1, but is not limited.

In one embodiment, the 3D printer 1 has a printing platform 11, a 3D nozzle 12 for spraying molding materials on the printing platform 11 to print a 3D model, and a 3D nozzle 12 for spraying ink on the 3D model A 2D spray head 13 for coloring a 3D model. In this embodiment, the 3D nozzle 12 mainly adopts a translucent molding material (for example, a completely transparent molding material or a translucent molding material), and the shrinking method of the present invention is mainly applied to Fused Deposition Molding (Fused Deposition Molding). Modeling, FDM) type 3D printer, but not limited to this.

As shown in FIG. 3A, to adopt the shrinking method of the present invention, first, an external computer (not shown) or the processor of the 3D printer 1 imports a 3D object (step S10), so that the processor can 3D objects are processed. Specifically, the 3D object refers to a virtual 3D object that has not yet been printed, and is stored in a 3D file (for example, a 3D file with an extension of .stl, .obj, .ply, etc.). The processor imports the 3D object after inputting and opening the 3D file.

The above-mentioned 3D file is a common format in the technical field, and will not be repeated here.

Then, the processor slices the imported 3D object to generate multiple object printing information and multiple color printing information of multiple printing layers (step S12). In this embodiment, multiple pieces of object printing information correspond to the printing paths of the sliced objects of each printing layer, and multiple color printing information correspond to the coloring content and/or coloring paths of the sliced objects of each printing layer. .

It is worth mentioning that each printing layer needs to use molding materials to print the sliced objects, so the slice processing will generate a corresponding piece of object printing information for each printing layer (for example, the The layer slicing process cuts the 3D object into 100 printing layers, which will generate 100 object printing information at the same time). However, not every sliced object of a printing layer needs to be colored. The slice processing only generates a corresponding color print information for the printing layer when the sliced object of a printing layer needs to be colored. Therefore, the quantity of the multiple color printing information is less than or equal to the quantity of the multiple printing layers.

Please also refer to FIG. 4A, which is a schematic diagram of the first layer of a 3D object according to a specific embodiment of the present invention. The main purpose of the present invention is that when the bottom surface of a 3D object needs to be colored (that is, the outer contour and internal structure of the cut layer object 3 that needs to be colored at least the printing layer need to be sprayed with ink), the processor can spray ink on the printing layer The corresponding color printing information is shrunk to enlarge the uncolored area on the sliced object 3, thereby improving the adhesion of the sliced object 3 to other adjacent sliced objects.

Returning to FIG. 3A, the processor further obtains the color printing information of the minimum color printing layer among the multiple printing layers after the layer cutting process is completed (step S14), and responds to the minimum color printing layer The color printing information of the colored printing layer performs shrinking processing to generate one stroke of shrinking color printing information (step S16).

As mentioned above, not every layered object of a printing layer needs to be colored, that is, not every printing layer has corresponding color printing information. In the above step S14, the processor mainly obtains the color printing information of all printing layers that needs to be colored and the lowest number of layers (that is, the color printing information closest to the bottom surface of the 3D model) from the multi-color printing information. ). In other words, in the above step S14, the processor mainly obtains the first color printing information generated by the slice processing.

Please refer to FIG. 4B at the same time, which is a schematic diagram of the first layer of the 3D object after being retracted in a specific embodiment of the present invention. As shown in FIG. 4B, after the above step S16, the processor generates the indented color printing information. If the processor colors the sliced object 4 of the same printing layer according to the color printing information after shrinking, the outer contour of the color portion 42 of the colored sliced object 4 will be a gap between the outer contour of the object portion 41 The distance of the shrinkage S. In this way, the sliced object 4 can retain a larger uncolored area (the size of the uncolored area corresponds to the size of the shrinkage S), thereby improving the adhesion between the sliced object 4 and other sliced objects .

In another embodiment, when the processor generates the indented color printing information, it can add adhesive information to the uncolored area at the same time. In this way, if the processor colors the sliced object 4 of the same printing layer according to the color printing information after shrinking, the sliced object 4 can be further strengthened by the adhesive applied on the uncolored area. Adhesion to other adjacent sliced objects.

It is worth mentioning that in step S16, the processor may further confirm the content of the color printing information of the minimum color printing layer to determine whether the shrinking process needs to be performed. As mentioned above, the main purpose of the present invention is to improve the overall structural strength of the 3D model. Therefore, as long as the layered objects on the bottom surface of the 3D model have sufficient adhesion, the processor does not need to color the color of the minimum printing layer. The print information performs the above-mentioned indentation processing.

Specifically, in step S16, the processor can determine whether the color printing information of the minimum coloring printing layer is as shown in the sliced object 3 in FIG. 4A, and fill the entire sliced object 3 with ink, or ink Whether the amount exceeds a certain proportion of the entire sliced object 3. In addition, when the processor determines that the content of the color printing information meets the preset shrinking standard (for example, the colored area exceeds 80% of the area of the entire sliced object 3), it performs the shrinking process to generate the shrinking Print information in the indented color. In this way, the quality of the 3D model printed by the 3D printer 1 can be effectively improved.

It is worth mentioning that, in this embodiment, the processor only performs the shrinking process on the color printing information of the lowest printing layer that needs to be colored, and generates the shrinking color printing information, and does not perform the color printing information on other printing layers. The color printing information executes the shrinking process. Specifically, in order for the user to see the color of the bottom surface of the printed 3D model from the bottom angle, the 3D model needs to be the outer contour and internal structure of the sliced object that needs to be colored at the minimum printing layer. Color (for example, the sliced object 3 shown in Figure 4A). As for the sliced objects of other printing layers, only the outer contours need to be colored (that is, the internal structure has a large number of uncolored areas). Therefore, even if the shrinking process is not performed on the color printing information of other printing layers, it will not harm the structural strength of the 3D model.

After step S16, the processor stores the multiple object printing information generated by the slice processing, multiple color printing information, and the indented color printing information generated by the shrinking processing (step S18). After step S18, the processor can import the multi-object printing information, multi-color printing information, and indented color printing information into the 3D printer 1 shown in Fig. 1 to enable 3D printing The machine 1 prints the physical 3D model corresponding to the 3D object.

Refer to FIG. 3B, which is a printing flowchart of a specific embodiment of the present invention. During printing, the 3D printer 1 sequentially obtains the object printing information of a printing layer (for example, the lowest first printing layer) among the plurality of printing layers, and according to the first printing layer The object printing information controls the 3D nozzle 12 to inject the molding material on the printing platform 11 to print the sliced object corresponding to the first printing layer (step S20).

Next, the 3D printer 1 determines whether the sliced object of the first printing layer needs to be colored (step S22). In one embodiment, the 3D printer 1 determines whether the currently printed printing layer (such as the first printing layer) has corresponding indented color printing information. If the currently printed printing layer does not have the corresponding indented color printing information, the 3D printer 1 determines that the layered object does not need to be colored. In this case, the 3D printer 1 returns to step S20 and obtains the object printing information of the next printing layer (for example, the second printing layer), and performs step S20 again according to the object printing information of the second printing layer . In this way, the 3D printer 1 controls the 3D nozzle 12 to inject the molding material on the printed layered object to print the layered object corresponding to the second printing layer.

It is worth mentioning that the thickness of each printing layer of the 3D object is very thin (for example, 0.2mm), as long as the selected molding material has better light transmittance, even if the 3D object is on the third printing layer, The four printing layers color the internal structure of the sliced object, and its color can still be regarded as the color of the bottom surface of the 3D model. Therefore, the indented color printing information does not necessarily correspond to the lowest printing layer (such as the first printing layer) in the 3D object.

If the currently printed print layer has the corresponding indented color print information, the 3D printer 1 controls the 2D nozzle 13 on the layered object according to the indented color print information corresponding to the print layer Ink is sprayed on to color the sliced object (step S24).

Then, after the sliced object of the printing layer (such as the first printing layer) is printed and colored, the 3D printer 1 obtains the object printing information of the next printing layer (such as the second printing layer) , And control the 3D nozzle 12 to eject the molding material according to the object printing information of the second printing layer to print the sliced object of the second printing layer (step S26).

After the layered object of the second printing layer is printed, the 3D printer 1 further determines whether the layered object needs to be colored (step S28). If the sliced object does not need to be colored, the 3D printer 1 returns to step S26 and obtains the object printing information of the next printing layer (for example, the third printing layer), and lists the objects according to the third printing layer To print the information, step S26 is executed again to print the sliced object corresponding to the third printing layer.

On the contrary, if the sliced object needs to be colored, the 3D printer 1 obtains the color printing information corresponding to the printing layer (such as the second printing layer), and controls the 2D according to the color printing information The nozzle 13 sprays ink to color the printed sliced object (step S30).

After step S30, the 3D printer 1 determines whether the 3D model corresponding to the 3D object has been printed (step S32), that is, it determines whether the current printing layer is the last printing layer of the 3D object.

If the 3D model has not been printed yet (that is, the current printing layer is not the last printing layer of the 3D object), the 3D printer 1 returns to step S26 and obtains the next printing layer (for example, the third printing layer) According to the object printing information of the third printing layer, step S26 to step S30 are executed again according to the object printing information of the third printing layer, until all the printing layers of the 3D object are printed and the coloring is completed.

Please refer to FIG. 5 at the same time, which is a schematic diagram of stacking sliced objects according to a specific embodiment of the present invention. As shown in FIG. 5, since the 3D printer 1 prints the color portion 42 of the layered object 4 of the lowest layer (for example, the first printing layer) of the 3D object according to the indented color printing information, the layered object The object part 41 of 4 has a larger non-coloring area (the non-coloring area is not stained with ink, but can retain the original adhesion of the molding material).

In this way, when the 3D printer 1 prints the sliced object 5 of the second printing layer on the sliced object 4 of the first printing layer, a better adhesion can be obtained, which is not caused by 3D printing. The machine 1 colorizes the internal structure of the sliced object 4 to reduce the adhesion of the two adjacent sliced objects 4, 5. Thereby, when the 3D model is printed and the user wants to remove the 3D model from the printing platform 11, the two sliced objects 4 and 5 will not be separated and damage the 3D model.

In the embodiment of FIG. 5, the 3D printer 1 controls the 2D nozzle 13 to color the sliced object 4 according to the indented color printing information to form the color portion 42, so the color portion 42 of the sliced object 4 may be The outer contour of the object part 41 of the sliced object 4 is not covered. However, the thickness of the sliced object 4 is quite thin, although the outer contour of the sliced object 4 is not colored (the purpose is to improve the adhesion between the sliced object 4 and the adjacent sliced object 5), but only other slices The outer contours of the layer objects are all colored, that is, it will not affect the overall appearance of the 3D model.

Please continue to refer to FIGS. 6 and 7, where FIG. 6 is a flow chart of shrinking in another specific embodiment of the present invention, and FIG. 7 is a schematic diagram of judging the direction of shrinking in a specific embodiment of the present invention. FIG. 6 is used to further explain step S16 of the flowchart of FIG. 3A to illustrate how the processor performs the shrinking process on the color printing information of the minimum color printing layer.

After the step S14 in FIG. 3A, the processor obtains the color printing information of the lowest color printing layer among the multiple printing layers of the 3D object (corresponding to the color part 42 shown in FIG. 7), and the processor The obtained color printing information is further analyzed to obtain a plurality of horizontal triangles constituting the color printing information (step S160). The horizontal triangular surface in this embodiment refers to the triangular surface parallel to the printing platform 11 (ie, parallel to the X-Y plane).

In the embodiment of FIG. 7, the color portion 42 formed by the first horizontal triangular surface 421 and the second horizontal triangular surface 422 is taken as an example. However, the color portion 42 may be formed by a large number of horizontal triangular surfaces. The number is not limited to two.

In step S160, the processor obtains a plurality of triangular faces in the color printing information, and uses the triangular face with the face normal vector n facing downward as the aforementioned horizontal triangular face. More specifically, the processor determines the angle between the normal vector n of the multiple triangle faces and a Z-axis vector (for example, (0,0,1)), and when the angle is equal to or approaching 0 degrees (That is, the surface normal vector n is parallel to the Z-axis vector), and the surface normal vector n is regarded as facing downward. Generally speaking, the multiple triangular faces included in the color printing information of the minimum color printing layer are all horizontal triangular faces with the face normal vector n facing downwards, but it is not limited to this.

After step S160, the processor obtains the directions of the multiple sides of the multiple horizontal triangular faces (step S162), and then determines a shrinking direction of the shrinking process according to the directions of the multiple sides (step S164).

In one embodiment, the processor is set to point the thumb of the human right hand toward the direction of the normal vector n of the horizontal triangle (in this embodiment, it is downward), and use the four fingers of the right hand to make a fist. The direction of multiple sides as a horizontal triangle (called the right-hand rule). In another embodiment, when drawing a 3D object, a designer can directly follow the above right-hand rule to number the multiple vertices of the horizontal triangle. In this case, the processor does not need to separately determine the directions of multiple sides of the horizontal triangle.

As shown in FIG. 7, the first horizontal triangular surface 421 is composed of a first vertex 4211, a second vertex 4212 and a third vertex 4213. The surface normal vector n of the first horizontal triangular surface 421 faces downward, so the directions of its multiple sides are clockwise. The second horizontal triangular surface 422 is composed of a first vertex 4221, a second vertex 4222, and a third vertex 4223. The surface normal vector n of the second horizontal triangular surface 422 faces downward, so the directions of its multiple sides are also clockwise.

In this embodiment, the processor uses the right vertical direction of the multiple sides of the horizontal triangular faces 421 and 422 as the retracting direction. In other words, the processor uses the direction of each side from the outer contour of the 3D object toward the internal structure of the 3D object as the retracting direction.

Go back to Figure 6. After step S164, the processor obtains the outer contour that needs to perform the shrinking process from the multiple sides of each horizontal triangle 421, 422 (step S166), and then according to the shrinking direction and preset shrinking The indentation process is performed on a plurality of outer contours (step S168), thereby generating the indented color printing information.

Specifically, in step S166, the processor determines whether any side of a horizontal triangular surface (for example, the first horizontal triangular surface 421) is adjacent to any side of another horizontal triangular surface (for example, the second horizontal triangular surface 422). Same, when it is judged to be the same (that is, the side is shared by two horizontal triangular faces 421, 422), it is deemed that the side is not the outer contour of the printing layer, and when it is judged to be different, it is deemed that the side belongs to The outer contour that needs to be indented.

As shown in FIG. 7, the edge formed by the first vertex 4211 and the third vertex 4213 of the first horizontal triangular surface 421 is the same as the edge formed by the third vertex 4223 and the first vertex 4221 of the second horizontal triangular surface 422. Therefore, the processor determines that the edge is shared by the first horizontal triangular surface 421 and the second horizontal triangular surface 422, and belongs to the internal structure of the printing layer rather than the outer contour. In this case, the processor does not perform shrinking processing on the edges.

Conversely, the edge formed by the first vertex 4211 and the second vertex 4212, the edge formed by the second vertex 4212 and the third vertex 4213, the edge formed by the first vertex 4221 and the second vertex 4222, and the edge formed by the second vertex 4222 The edges formed by the third vertex 4223 and the third vertex 4223 are not the same as the edges of other adjacent horizontal triangular faces. Therefore, the processor determines that the above multiple edges belong to the outer contour of the printing layer. In this case, the processor performs shrinking processing on the multiple edges.

In another embodiment, the processor may also determine whether any two adjacent vertices of a horizontal triangular surface (such as the first horizontal triangular surface 421) are connected to another adjacent horizontal triangular surface (such as the second horizontal triangular surface 422). ) Any two adjacent vertices are the same, when it is judged to be the same (that is, the two adjacent vertices are shared by the two horizontal triangular faces 421 and 422), it is determined that the edge formed by the two adjacent vertices does not belong to When the outer contour of the printing layer is judged to be different, it is determined that the edge formed by the two adjacent vertices belongs to the outer contour that needs to be indented.

For example, the processor may merge any two adjacent vertices of the first horizontal triangular surface 421 into a fixed function, and calculate the first value through the function, and then compare any two of the second horizontal triangular surface 422 with each other. The neighboring vertices are merged into the same function, and the second value is calculated through the function. If the first value is equal to the second value, the processor can determine that the two imported vertices are the vertices shared by two flat and horizontal triangular faces 421 and 422, and therefore determine that the edge formed by the two adjacent vertices does not belong to The outer contour of the printing layer does not need to be indented.

However, the above are only part of the specific implementation examples of the present invention, and the processor of the present invention can also determine whether two edges are the same edge according to other technical means, and are not limited to the above implementation examples.

。In the above embodiment, the processor performs the shrinking process according to the shrinking direction and the preset shrinking amount. In another embodiment, the processor can dynamically calculate the shrinkage amount according to the following formula:

.

In the above formula, S is the minimum shrinkage amount used by the processor to perform shrinkage processing; a is the shrinkage parameter> 1, and as the 3D nozzle 12 uses different molding materials, the shrinkage parameter will correspond to Change; w is a nozzle diameter of the 3D nozzle 12 (that is, corresponding to the width of the molding material ejected by the 3D nozzle 12); d is the distance error between the 3D nozzle 12 and the 2D nozzle 13 in the structure. However, the above are only multiple implementation examples of the present invention, but not limited thereto.

Through the shrinking method of the present invention, it can be ensured that even if the 3D printer colorizes the bottom surface of the 3D model, it will not affect the overall structural strength of the 3D model, and the printed 3D model can have better printing quality .

The above are only preferred specific examples of the present invention, and are not limited to the scope of the patent of the present invention. Therefore, all equivalent changes made by using the content of the present invention are included in the scope of the present invention in the same way. Bright.

1‧‧‧3D printer

11‧‧‧Printing platform

12‧‧‧3D print head

13‧‧‧2D print head

14‧‧‧Control lever

2‧‧‧3D model

21‧‧‧The first layer of sliced objects

22‧‧‧Second layer of sliced objects

3, 4, 5‧‧‧Sliced objects

41‧‧‧Object part

42‧‧‧Color part

421‧‧‧The first horizontal triangle

4211、4221‧‧‧First vertex

4212, 4222‧‧‧ second vertex

4213, 4223‧‧‧The third vertex

422‧‧‧Second horizontal triangle

S‧‧‧Inward shrinkage

n‧‧‧face normal vector

S10~S18‧‧‧Indentation steps

S160~S168‧‧‧Indentation steps

S20~S32‧‧‧Printing steps

Figure 1 is a schematic diagram of a related art 3D printer.

FIG. 2A is a schematic diagram of the first layer of a related art 3D object.

FIG. 2B is a schematic diagram of the second layer of the related art 3D object.

Figure 3A is an indented flow chart of a specific embodiment of the present invention.

FIG. 3B is a printing flow chart of a specific embodiment of the present invention.

4A is a schematic diagram of the first layer of a 3D object according to a specific embodiment of the present invention.

4B is a schematic diagram of the first layer of the 3D object after shrinking in a specific embodiment of the present invention.

Fig. 5 is a schematic diagram of stacking sliced objects according to a specific embodiment of the present invention.

Fig. 6 is an indented flow chart of another specific embodiment of the present invention.

FIG. 7 is a schematic diagram of judging the retracting direction according to a specific embodiment of the present invention.

S10~S18‧‧‧Indentation steps

Claims (12)

A method for shrinking the colored area of a color 3D object, including: a) Importing a 3D object by a processor; b) Performing all layer processing on the 3D object to generate multiple printing information of multiple printing layers And multiple color printing information; c) Obtain a color printing information of the minimum color printing layer; d) Perform an indentation process on the color printing information of the minimum color printing layer to generate a The color printing information after shrinking, wherein the shrinking process is to shrink the color printing information of the minimum color printing layer obtained by processing the cutting layer from an outer contour of the corresponding object printing information to Enlarge the uncolored area on all objects corresponding to the minimum color printing layer to improve the adhesion between the sliced object and other adjacent sliced objects above; and e) store the multiple objects for printing Information, the multi-color printing information, and the indented color print information, wherein the multi-object print information, the multi-color print information, and the indented color print information are applicable to an FDM-style 3D A printer, the FDM type 3D printer has a 3D nozzle for spraying molding material and a 2D nozzle for spraying ink, wherein the 3D nozzle uses a transparent molding material, the 3D printer According to the indented color printing information, the 2D nozzle is controlled to spray ink on the molding material sprayed by the 3D nozzle according to the object printing information corresponding to the same layer. The method for shrinking the colored area of a colored 3D object according to claim 1, wherein step d) includes the following steps: d1) obtaining a plurality of horizontal triangles that constitute the minimum printing layer to be colored; d2) Obtain the directions of the multiple sides of the multiple horizontal triangles respectively; d3) determine a shrinking direction according to the directions of the multiple sides; d4) Obtain from the plurality of edges the outer contours that need to perform the indentation processing; and d5) perform the indentation processing on the plurality of outer contours according to the indentation direction and a shrinkage amount. The method for shrinking the colored area of a color 3D object as described in claim 2, wherein step d4) is to determine whether any side of a horizontal triangle is the same as any side of another adjacent horizontal triangle, and judge it as not At the same time, it is determined that the edge belongs to the outer contour that needs to perform the indentation processing. The method for shrinking the colored area of a colored 3D object as described in claim 2, wherein step d4) is to determine whether any two adjacent vertices of a horizontal triangle are adjacent to any two of another adjacent horizontal triangle The vertices are the same, and when it is judged that they are not the same, it is determined that the edge formed by the two adjacent vertices belongs to the outer contour that needs to perform the shrinking process. The method for shrinking the colored area of a colored 3D object as described in claim 2, wherein the surface normal vectors of the plurality of horizontal triangular surfaces face down, and step d2) is to point the right thumb to the direction of the surface normal vector, and The fist direction of the four fingers of the right hand is taken as the direction of the multiple sides. The method for shrinking the colored area of a color 3D object according to claim 5, wherein step d3) is to use the right vertical direction of the multiple sides as the shrinking direction. The method for shrinking the colored area of a color 3D object according to claim 5, wherein when the angle between the normal vector of the plurality of horizontal triangular faces and a Z-axis vector is equal to or approaching 0 degrees, it is regarded as the The face normal vector faces down. The method for shrinking the colored area of a colored 3D object according to claim 1, wherein the 3D nozzle adopts a completely transparent or semi-transparent molding material. The method for shrinking the colored area of a color 3D object according to claim 1, wherein the 3D printer is a Fused Deposition Modeling (FDM) 3D printer. The method for shrinking the colored area of a color 3D object according to claim 1, wherein the shrinking amount used in the shrinking process is: S=a×w+d, where S is a minimum shrinking amount, and a is> An indentation parameter of 1, w is a nozzle diameter of the 3D nozzle, and d is a distance error between the 3D nozzle and the 2D nozzle. The method for shrinking the colored area of a color 3D object according to claim 1, which further includes the following steps: f) controlling the 3D nozzle to print all layers corresponding to the printing layer according to the object printing information of a printing layer Object; g) determine whether the sliced object needs to be colored; h) when the sliced object does not need to be colored, repeat step f) and step g) based on the object print information of the next print layer; and i ) When the sliced object needs to be colored, the 2D nozzle is controlled to color the sliced object according to the indented color information corresponding to the printed layer. The method for shrinking the colored area of a color 3D object as described in claim 10, which further includes the following steps: j) After step i), control the 3D nozzle to print the next print based on the object print information of the next print layer The sliced object corresponding to a printing layer; and k) controlling the 2D nozzle to color the sliced object according to the color information corresponding to the next printing layer.

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