Gpu material assignment for 3d printing using 3d distance fields

Abstract

A method includes selecting a voxel from a three-dimensional build space and for the selected voxel, determining a distance field value relative to a digital model of a 3D part in the three-dimensional build space. The distance field value is then used to select at least one material selection rule and a feature of the voxel is applied to the at least one material selection rule to identify a material designation for the voxel. The material designation indicates no material is to be placed at the voxel when the material selection rule identifies no material for the voxel and the material designation indicates at least one material is to be placed at the voxel when the at least one material selection rule identifies the at least one material for the voxel. The material designation for the voxel is then output for use in printing the 3D part using an additive manufacturing system.

1 . A method comprising:
 for each of a collection of voxels in a three-dimensional build space:
 selecting a voxel in the collection; 
 for the selected voxel, determining a distance field value relative to a digital part model in the three-dimensional build space; 
 using the distance field value to select at least one material selection rule; 
 applying a feature of the selected voxel to the at least one material selection rule to identify a material designation for the selected voxel, wherein the material designation indicates no material is to be placed at the selected voxel when the material selection rule identifies no material for the selected voxel and wherein the material designation indicates at least one material is to be placed at the selected voxel when the at least one material selection rule identifies the at least one material for the selected voxel; and 
   outputting the material designations for the collection of voxels for use in printing a 3D part using an additive manufacturing system.   
     
     
         2 . The method of  claim 1  wherein the feature of the selected voxel applied to the at least one material selection rule comprises the distance field value. 
     
     
         3 . The method of  claim 2  wherein the at least one material selection rule comprises a periodic function and wherein the material selection rule identifies no material for the selected voxel when an output value of the periodic function is in a first range and wherein the material selection rule identifies a material for the selected voxel when the output value of the periodic function is in a second range. 
     
     
         4 . The method of  claim 3  wherein the periodic function is a function of the distance field value. 
     
     
         5 . The method of  claim 3  wherein the periodic function comprises the distance field value summed with a base periodic function. 
     
     
         6 . The method of  claim 1  wherein the feature of the selected voxel applied to the at least one material selection rule comprises a position of the selected voxel in the three-dimensional build space. 
     
     
         7 . The method of  claim 6  wherein the at least one material selection rule comprises a periodic function and wherein the material selection rule identifies no material for the selected voxel when an output value of the periodic function is in a first range and wherein the material selection rule identifies a material for the selected voxel when the output value of the periodic function is in a second range. 
     
     
         8 . The method of  claim 7  wherein the periodic function is a function of the position of the selected voxel in the three-dimensional build space. 
     
     
         9 . The method of  claim 1  wherein using the distance field value to select at least one material selection rule further comprises using the distance field value together with a determination of whether the selected voxel is in a support region of the part to select the at least one material selection rule. 
     
     
         10 . The method of  claim 1  wherein using the distance field value to select at least one material selection rule further comprises using the distance field value together with a feature of a closest point on the digital part model to the selected voxel to select the at least one material selection rule. 
     
     
         11 . The method of  claim 1  further comprising determining a second distance field value relative to a second digital part model in the three-dimensional build space and selecting one of the second distance field value and the distance field value to select the at least one material selection rule. 
     
     
         12 . The method of  claim 11  wherein selecting one of the second distance field value and the distance field value comprises using respective features associated with closest points on the digital part model and the second digital part model to the selected voxel to determine which distance field value to select. 
     
     
         13 . The method of  claim 11  wherein selecting one of the second distance field value and the distance field value results in a material selection that removes interference between the 3D part and a second 3D part when the selected voxel is located in both the digital part model and the second digital part model. 
     
     
         14 . The method of  claim 1  further comprising determining a second distance field value relative to a second digital part model in the three-dimensional build space and using both the distance field value and the second distance field value to select respective material selection rules. 
     
     
         15 . The method of  claim 14  wherein applying the feature of the selected voxel to the at least one material selection rule comprises applying the feature of the selected voxel to a material selection rule formed by combining the respective material selection rules selected using the distance field value and the second distance field value. 
     
     
         16 . The method of  claim 1  wherein determining a distance field value for the selected voxel comprises using the values in z-buffers of a graphics processing unit to determine distances from the selected voxel to a plurality of locations on the digital part model, and using the shortest distance to determine the distance field value. 
     
     
         17 . The method of  claim 1  wherein the distance field value is in a first range of values if the selected voxel is outside of the digital part model, is in a second range of values if the selected voxel is within the digital part model and is a singular value if the voxel is on the boundary of the digital part model. 
     
     
         18 . The method of  claim 1  wherein the voxel forms part of a lattice structure. 
     
     
         19 . The method of  claim 1  further comprising printing the 3D part using the additive manufacturing system and the output material designations for the collection of voxels. 
     
     
         20 . The method of  claim 1  wherein outputting the material designations for the collection of voxels comprises outputting a bitmap for a surface-like collection of voxels. 
     
     
         21 . The method of  claim 1  wherein outputting the material designations for the collection of voxels for use in printing the 3D part comprises generating print instructions from the material designations for the collection of voxels for use in printing the 3D part. 
     
     
         22 . The method of  claim 21  wherein the print instructions comprise toolpaths. 
     
     
         23 - 43 . (canceled)