3D Renderer: volume cropped by 1 in every direction

With raycast renderer (=software renderer), in the 3D renderer the volume is cropped by 1 voxel in every direction:


The problem seems to only exist for the software renderer; the GPU renderer however produces strange results for small volumes.

Look at the raycast renderer (software renderer) code in the 3D rendering module. The issue mentions the volume is cropped by 1 voxel in every direction. Start by finding the volume bounds handling in the raycasting algorithm, likely in a file related to volume rendering or raycasting. Compare with the GPU renderer's bounds handling to see the difference. Check for off-by-one errors in loop bounds or coordinate transformations. Running the software renderer on a small test volume can help verify the fix.

Written by the indexing model from the issue text.