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houGenie

Normal map baking methods

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Hi guys,

I am normal baking my mesh and have some questions.

What method does 3d Coat use for normal baking? Is it the projection method or is it the explicit surface normal method? It seems, that 3d Coat always smooths my normals when baking, even when I activate lock normals in baking menu. Then after the baking process if I deactivate the normal map (painting room) one sees that alle hard edges are smoothed. But unfortunately because of this you have way more gradients in the normal map. The only way to get rid of that is to bevel hard edges in the low poly model before normal baking. Is there some better method ? And how on earth can I prevent that 3d Coat smooths my hard edges?

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Hi

3DC use two baking methods: Retopo room > Bake > Bake Scan settings

- Snap to closest along normal

- Snap to outer surface

Snapping method.jpg

 

 

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It is better to avoid sharp angles between faces (like in example, retopo mesh between A and B), even angle a little less 90 degrees are not recommended, it will lead to problems if you are using 3D-Coat's method for calculating normals (Edit ->Preferences>Normals calculation).

Maya normals calculation method will work correctly in this case, so if you need sharp angles, use Maya normals calculation in Preferences. This is related to method of calculation. 3D-Coat calculates normals as  weighted average of neighbor faces, weight is proportional to face square. It allows to display bevel between faces correctly.


But if there is sharp angle between big and small faces then vertex normal will be negative to small face normal and baking on that face will fail. Maya's method calculates vertex normal as arithmetical average of neighbor faces normals. It is more appropriate for baking, but not good to display meshes without normalmap.

Generally we recommend to add bevel between sharp edges.

Happy_baking_guide2.pdf

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I've also had trouble getting the Lock Normals feature in the Bake menu working (according to this thread it seems the feature currently isn't working). 

As a workaround you can export the retopo object (Retopo menu > Export) and import it to Maya/3DS Max/etc to set up your smoothing groups, then re-import the object into the Paint room and use the Bake menu > Bake sculpt mesh onto paintroom mesh option, which will bake details from your sculpt object to your paint object without interfering with the previously defined smoothing groups.

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This issue was reported.

If you like please send support request to Andrew Shpagin at

support@3dcoat.com

Thx.

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3DC preserves import/export of smoothing groups via normals. Normals signal that some edge is sharp or smooth.

Smoothing groups are supported via OBJ format. But you need to export normals also from your 3D-model app. 3D-Coat uses normals in OBJ file to recover smoothing groups.

Please check.

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When using hard edges (or smoothing groups), it’s important to ensure that you break apart your UV islands along all hard edge borders. If you use hard edges but do not split your uvs, you will get seam artifacts as each face will try to bake onto the hard edge line.

hardedgeuvs.jpg

Source

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Yes, normals are exported and can be seen in athore apps. The only thing which seems to work is the auto smoothing group option. But then there are seams on the baked normal map, seems like no projection method is used. 

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16 minutes ago, Carlosan said:

When using hard edges (or smoothing groups), it’s important to ensure that you break apart your UV islands along all hard edge borders. If you use hard edges but do not split your uvs, you will get seam artifacts as each face will try to bake onto the hard edge line.

hardedgeuvs.jpg

Source

Carlosan, yes of course. But you get the seams also when you have hard edges, UV splits and use the explicit surface normal method and not the projection method. Because the normals will have 90 degrees on hard edges and the rays will not cover all the details. That is the reason the projection method is used. 

Edited by houGenie

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I am reporting this issue again -added to the old one-

Will be very useful if you send this support request to Andrew Shpagin at

support@3dcoat.com

Thx

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