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Possible displacement map bug


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When I got the new version of 3DC. using windows version 3.1.17 non-cuda (3DC user since Dec,2007) I encountered problems with displacement mapping with imported Obj files (merging for Voxel work). I could not bake a correct displacement map. Starting from a Voxel primitives there is no problem baking a displacement map. I knew 3DC should be able to bake a displacement map for imported obj files (merging for voxel work) without having to save up to a 16 meg obj file to get one. Therefore I did hours of testing trying to figure out if I was causing the problem or something in the software. I made all kinds of models, change the Obj material file information at times, tried many different settings and worked on a number of possible solutions. I finally hit upon this possible bug as to what is causing the displacements maps to bake incorectly. In finding the possible bug, I also found a solution.

Steps to problem. (using a simple uv mapped obj model for testing)

Clear voxel primitive.

merge obj file.

Choose "Yes" to keep scale and position.

In retopo room import your same low polygon uv mapped obj model and snap to voxels. Also tested quadrangulate and auto seams, same baking problem.

Do some simple extrusions.

In retopo room resnap to voxels, can be left undone if voxel extrusions are not to extreme. "Not worried about uv stretching on my testing" Also tested quadurangulate and auto seams

Next in retopo room "merge into scene" mircoverts . I also chose a high carcass level. tested all carcass levels and no-subdivision too. I also tested all the other merging options.

Bake displacement texture(zero level is black not normalized) using texture baking tool either from the retopo room or paint room, the created displacement map is no good. (picture included titled "bad displacement.jpg")

I closed 3DC before starting new work as it seems that the program will leave left over junk from your previous voxeling when you don't close the program... My testing always started with a clean plate just to be sure.

Solution:

Only change the below step, keep all other steps in their order

Choose "No" to keep scale and position.

Add this step You have to use the transform tool to resize your imported model to fit the voxel sculpt in the retopo room.

Now after following the rest of the steps you get a correct baked displacemnt map.

Now, it still could be user error or a bug on my verison only but I thought it best to post this as displacment mapping on imported models for voxel sculpting is a feature that is highly used.

I included pictures showing the bad displacement map, the good one, and a picture of a low-polygon model (appox 2500 polys) with the good displacement render.

I reduced the size of the displacment maps for uploading here...

post-518-12597793873794_thumb.jpg

post-518-12597794259822_thumb.jpg

post-518-12597794924242_thumb.jpg

post-518-12597795569672_thumb.jpg

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Seems the root of the problem in "zero level is black not normalized" + JPG file. Jpg can't handle well not-normalized data. Use tiff or better exr for not-normalized displacement. Use jpg only for normalized displacement.

I used tiff files, I only converted to jpg for uploading to show the difference... Never use jpgs for Baking. Sorry my post seem to said that I used the jpgs but was only meant for uploading purposes.

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