[Bf-committers] Triangulate modifier

metalliandy metalliandy666 at googlemail.com
Sat Nov 10 19:18:49 CET 2012

I'm not sure I get what you are suggesting here, but the point of the 
modifier (and why it was requested) is to give consistent triangulation 
between the baker and the final mesh before baking normal maps. These 
can then be exported into a game engine, while still maintaining a 
non-destructive work flow and retaining the original topology of the 
initial mesh.
Normal maps require that the geometry/topology of the low poly mesh is 
100% identical to the mesh used for baking in order to work correctly, 
otherwise the normal map will likely be compensating for edges/faces 
that are flipped another way and thus provide an incorrect result and 
therefore shading errors in the final result.
The triangulation modifier is the most reliable way that I am aware of 
to do this in a non destructive way while guaranteeing identical 
topology between the mesh used for baking and the final exported asset. :)

On 10/11/2012 16:57, CoDEmanX wrote:
> We already have tesselation (tris+quad), and you can turn the quads into
> triangles by taking vert 0,1,2 and 2,3,0. That will give you a
> triangulation like seen in Blender viewport. So why not use tessfaces?
> I'd like to have a viewport option to show triangulation edges, but I
> can't see the reason for triangulation modifier.
> btw. I wrote a little script to make tessellation visible why creating a
> new mesh from tessfaces:
> http://blenderartists.org/forum/showthread.php?255806-Release-Tessfaces-to-new-mesh-(makes-tessellation-visible)
> Am 10.11.2012 15:10, schrieb Morten Mikkelsen:
>>>> When baking with an all quad mesh, the triangulation that is done
>>>> internally in Morten's TS might not match the manual triangulation that
>>>> the user applies on export, which potentially could cause issues because
>> This is not exactly the issue. Let me clarify.
>> The mikktspace part is done at quad level if there are quads and will
>> always give the same
>> tangent spaces at vertex level no matter what the order of vertices or
>> faces is.
>> This is its very strong advantage which other tangent space calculators
>> can't do.
>> After mikktspace has already run the problem occurs at a later stage
>> because before rendering/baking triangulation has to have been performed.
>> So the issue is eventhough the tangent spaces at the vertices aren't
>> impacted by how quads are triangulated (since triangulation happens later)
>> the interpolated tangent space is heavily impacted by which diagonal is
>> picked. Similar to how Gouraud shading is heavily impacted by which
>> diagonal is picked. So eventhough tangent space is consistent at the
>> vertices you get problems if baker and render don't pick the same
>> triangulation
>> due to differences in the interpolated tangent space.
>> I should mention I am using "render triangulation" loosely here since it
>> can happen in a lot of places though for a game it would typically happen
>> somewhere in the engine's tools pipeline. Anyway the advantage to this
>> modifier is it enforces a consistent triangulation which will be received
>> by both baker and renderer (incl. Blender's renderer). Further, this is
>> achieved without causing permanent triangulation.
>> It's a sensible practice which is already used by artists in other modeling
>> products.
>> Morten M.
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