Weird normal maps

[Trasna]

Hi,

 

       I'm having a very difficult time with normal maps, they display absolutely fine in 3D coat but when I move them across to Blender cycles or indeed any other application they are a complete mess.

I am selecting that I want to export normal maps for Blender/Maya but that doesn't appear to be the issue.

 

This is best illustrated in pictures ....

 

Here's my retopo'd object with an automatic unwrap, not done anything here except unwrap it and then I hit bake normal / per pixel to get it into the paint room.

 

 

This is the object in 3D Coat looking fine ..... although based on the normal map it shouldn't be looking fine at all as far as I can tell.

 

 

Then I do an export of the object and it's textures specifying blender/maya as the app for the normal map format. And here is the result in blender cycles ....

 

 

The thing to note is you can clearly see the UV islands from the automatic retopo and looking at the uvmap itself it seems fairly obvious that the map is incorrect as the separate uv island pieces do not match up and you can see clear colour differences across the seams of the islands in the map if you reassemble the constituent parts.

 

I've been round and round this and ended up deciding I must be doing something dumb here but I can't work out what it is, I rarely post as you can usually find an answer to this stuff online but this time around I've searched and turned up nothing, maybe I'm searching on the wrong keywords.

 

Any guidance much appreciated

 

Ash.

 

 

 

 

 

 

[Carlosan]

could you share pics with your preferences and export settings ?

[Trasna]

Hi,

 

       Thanks for offering assistance. I'm attaching the requested details ...

 

 

 

I've also uploaded to google drive the 3D Coat project I'm having issues with here -- > https://drive.google.com/folderview?id=0B5ZmVufmkjnwOFlkOExsd04zV1U&usp=sharing

 

Rgds, Ash.

 

 

 

Edited September 29, 2015 by Trasna

[Carlosan]

You are not using bake command at retoporoom ?

 

[Trasna]

Yes, I use that initially to bake the detail from the voxel mesh to the retopo mesh.

 

Workflow is as follows:

 

1) voxel sculpt (I haven't done any surface sculpting on this mesh so it's straight from voxel to autopo)

2) autopo the mesh, defaults, nothing fancy

3) uv map the mesh by using the auto mode in retopo room, I also pak the uv's without any flipping or rotating just to make sure it isn't something like that causing the issue.

4) run the bake to bake the normal map and get the retopo mesh into the paint room. As part of this I set the inner and outer cages appropriately, easily done on this particular mesh.

5) paint the mesh (which in this case is just a layer fill using the bumped plastic smart material)

6) run an export of the .obj and it's textures to disk

7) import into blender and setup the cycles renderer with the textures

any further changes and I just do texture bakes rather than exporting the low poly mesh again

 

Rgds, Ash.

Edited September 30, 2015 by Trasna

[Carlosan]

big scale, better 1

 

model non uniform

 

use to global space

 

object very small, more big better

 

use bake command in retopo room

 

model in paint room

 

Use file export

 

----------------------------------------------------

Blender auto-normalizing normal maps, you need to use Normal edit modifier

https://www.blender.org/manual/modifiers/modify/normal_edit.html

[Trasna]

Thanks for the updates, after a bit of messing around I got a good render at last

 

I didn't need to use the blender normal edit modifier but I did spot an error in my node setup in that I was outputting colour data instead of non colour data, however previous to your tips above this wouldn't have made any difference as the normal map was not correct anyway (it is now).

 

 

 

[Carlosan]

Great !

[Trasna]

Well I thought this was solved but it isn't, whilst I managed to get one sculpt to work I am unable to repeat this and am still getting very unacceptable results for my sculpts, to the point that on my current client engagement I've had to scrap using 3D coat and go back to using Blender to box model complex shapes. Really very unhappy at the moment as box modelling in blender is extremely slow for the type of work I'm doing and having bought 3D coat to do this work not being able to use it is very frustrating. The issue is still incorrect normal maps that show up the islands from the uv unwrap and also the underlying mesh surface without any smoothing.

 

I've gone over and over it, the sculpt is in global space, the size is good, the inner and outer bake shells are fine, it's not non-uniform, I've lost an entire days work to trying to resolve it and I'm no further forward than I was at the start of the day.

[Trasna]

After a bit of messing about in blender I've switched over to trying the bakes in xnormal to see if it creates something different as I just can't get the organic shapes I want easily in blender.

[Trasna]

OK, took all day but I have finally fixed it. It took a number of things but the main one was selecting all the edges in the exported mesh and clicking smooth edges in blender, this then allowed the mesh to be smoothed properly instead of flat shaded. Also upping the poly count on the retopo mesh as the normal map wasn't able to cope with the low poly retopo mesh I was using.

[Trasna]

I should mention I had to do the smoothing in edit mode on the edges themselves not the faces, just clicking 'Smooth' in object mode had no effect at all.