I don't think you're correct. The gl code receives quads.
It's arbitrary what happens to the quads once opengl gets them.
The modifier will enforce correctness.
On Wed, Nov 14, 2012 at 1:10 PM, CoDEmanX codem...@gmx.de wrote:
OBJ exporter offers a Triangulate Faces option. If enabled, it won't
export quads, but take the tessfaces and turn quads into tris by using
vert 0,1,2 for one tris, and 2,3,0 for another. This way, you get what
you see in viewport, non-destructive and without extra calculations.
Search for f_v_iter:
https://svn.blender.org/svnroot/bf-extensions/trunk/py/scripts/addons/io_scene_obj/export_obj.py
Am 14.11.2012 21:31, schrieb Morten Mikkelsen:
The important thing is that any proposed solution will work with export
too.
If the obj exporter is still exporting quads and beyond then this is not
a
solution.
The modifier solution will make sure the exporter when exporting the dm
exports the same
triangulation. If what you are proposing does that then it's probably
fine.
On Tue, Nov 13, 2012 at 4:07 PM, Brecht Van Lommel
brechtvanlom...@pandora.be wrote:
Tessfaces contain both quads and triangles. The render engine can
store quads natively (uses less memory) and has its own splitting
algorithm which is different than what OpenGL does. Perhaps it would
not be a bad thing to add an option to Mesh datablocks to disable that
smart render engine splitting and have it the same as the viewport,
and enable it by default even.
I don't know how important the smarter splitting it is in practice, in
Cycles I intentionally did not add it because it can pop in animation
and be inconsistent with the viewport, did not see complaints about it
so far.
Brecht.
On Wed, Nov 14, 2012 at 1:00 AM, CoDEmanX codem...@gmx.de wrote:
Alright, maybe what i had on mind isn't possible in your case.
As Blender has a tessface cache, I thought it should be used throughout
the application for everything that requires tessellated mesh geometry.
Polygon and tessface data can be accessed at the same time, so this is
basically non-destructive as well. What is missing IMO is a checkbox to
toggle display of tessfaces (we already see tesselated faces, but they
aren't outlined etc.)
A modifier might offer an extra ability of editing the triangulated
mesh
non-destructively, not sure if possible, but if so, it would be great
to
be able to adjust triangulation in certain spaces (tessfaces don't make
up nice triangles)
Am 14.11.2012 00:25, schrieb metalliandy:
The point of the modifier is not how it is triangulated, it is that
the
triangulation is non destructive and can be visibly toggled on and off
by the user at will and without the need for undo steps :)
Also that quote you was from me, not Morten and I was 100% accurate.
Morten replied and said in his reply to me
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.
I hope that clears everything up :)
-Andy
On 13/11/2012 23:12, CoDEmanX wrote:
Sounds to me like there is an inconsistency somewhere in Blender,
which
causes the difference in mesh geometry between what baker uses and
the
stored/exported data... Shouldn't everything in Blender use
tessfaces,
if triangles are required?
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 [...] - Morten Mikkelsen
There shouldn't be manual
