Should one recompute tangent basis if geometry, uv, shading (hard edges/smooth groups) are changed?

EugeneTheSage

The title basically describes my question. Should I create tangent basis from scratch before exporting to marmoset or SP for baking/texturing if I committed any of the enlisted changes?

Eric Chadwick

Yes. What software are you exporting from? 

iam717

mmm, others probably know more than, i...

However it depends, if you just finalized a mesh and then posed it and are not happy with the "stretching" and want to correct it by also posing the highpoly in the same way and doing whatever you have to do to figure and correct all that, then, not really.  Taboo to say i suppose but generally if the entire movement situation isn't insanely drastic or even noticeable, idc usually to do that, since it would take a long time for something small.  (the "reviewing" of peers or general audiences) isn't very long, i give maybe 3-10 seconds the most to any imgs i see, unless i am in shock and want to examine the more technical side of things on the appearances of projects/finished works.  If you have yet to bake/texture it probably won't look right.

Taking all these into consideration also, for your final decision on this matter.

I say yes, if its production and they have to have 100% perfection quality, i say not really if its just portfolio (practice) or temporary project as people seem to love to throw away all the time they spent making pretty decent works of art, for more current pieces that show current quality level.  (decent works of bobotheseal) as an example from 15+ years ago is still fine with me today and do not see the need for anyone to get rid of their previous works, especially if someone wanted to "remember" some of those times or see those works today.  (harddrives fail, to the save img comments)

EugeneTheSage

IEric Chadwick said:

Yes. What software are you exporting from? 

I use Foundry Modo. I create a tangent basis here and export it to Marmoset and Painter. By the way, painter always says that some tangent values are null and will be recomputed

Eric Chadwick

What format are you exporting from Modo?

I know when exporting glTF from 3ds Max there is the option to include tangents or not.

So it could be that the exporter either doesn’t support tangents, or else is mangling them. Could also be that Painter is not importing them correctly.

EugeneTheSage

Eric Chadwick said:

What format are you exporting from Modo?

I know when exporting glTF from 3ds Max there is the option to include tangents or not.

So it could be that the exporter either doesn’t support tangents, or else is mangling them. Could also be that Painter is not importing them correctly.

I'm using fbx, and I choose to export tangents. There are no problems, just wanted to know if I need to delete and create tangent basis each time I move the edge, split the uvs, add a hard edge

Klunk

Do a test, a simple obvious mesh and do what you propose..... have a look at the result of using an old basis vs the new basis then you'll know.