Obj Smooth Surface Normals

Started by Ashley, September 19, 2015, 12:56:46 AM

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Ashley

Ah yeah, that thread is a good read. I have seen it before, in fact it was the first attempt I had with VD out of Zbr.
Following it I was able to get a result, but only from lots of tweaking.

Do you have a .mtl that actually shows vn values or do you assume they are in the
.mtl files?


I was thinking a similar thing, maybe I could copy past the vn into one file. But no when I open the .mtl its just container for maybe .bmp assignment?

Its another Zbr quirk but it would be good to have TG generate normals, or I wonder if there might be a way to assign these inside an .obj internal network?

Cheers
Ash

Hetzen

I'm pretty sure smoothed surface normals are embedded in the .obj mesh.

When setting up smoothing groups, it's part of the poly edit process not the texturing.

Hetzen

Quote from: Ashley on September 22, 2015, 03:56:33 PM
Its another Zbr quirk but it would be good to have TG generate normals, or I wonder if there might be a way to assign these inside an .obj internal network?

Can you take your zbrush mesh into a 3d app and apply auto smooth, setting your angle threshold between surfaces to define hard edges in the smoothing groups?

Hetzen

Just been looking on Modo forums. Modo seems to use smoothing in texture only, where as Maya and Max bake that data onto the mesh. It maybe worth asking someone with the app to help out. Otherwise download a 30 day trial if you're in a fix. As I said earlier, .obj exports smoothing withing the mesh data and not in the .mtl file.

Ashley

Thnx Hetzen,
It's all good, just confirming that indeed that was why TG didn't smooth.

Cheers
Ash

j meyer

It's not a ZB quirk - from my point of view - but a way to keep .obj file sizes
kind of moderate.Ever tried to add normals to a high poly mesh?  I did. Sizes
can get really much bigger.

Anyway,cool you got it sorted. :)

Ashley

Quote from: j meyer on September 23, 2015, 11:52:12 AM
It's not a ZB quirk - from my point of view - but a way to keep .obj file sizes
kind of moderate.Ever tried to add normals to a high poly mesh?  I did. Sizes
can get really much bigger.

Anyway,cool you got it sorted. :)

That's a good observation. I've noticed the same mesh from Zbrush, exported from Maya is significantly larger.
Zb can handle about 1.3GB obj file on import. So that's a nice tip to load heavier meshes.

fyi I like the quirky apps ;-)

Ashley

So does TG export vn with the obj?
If so is there a way to disable this? Zbrush taps out at loading obj larger than 1.3gigs.
As pointed out above, not saving vn with obj lowers the file size.

This might be a good feature for those exporting massive terrains.

Cheers
Ash

Matt

The Micro Exporter allows you to choose whether or not to export normals. The same for UVs.

If exporting an OBJ from some other kind of object, it depends whether normals were loaded in the first place, which depends the "use smooth normals" in that object's settings. If you turn that off, really what it's doing is stopping it from importing normals in the first place, so then there are no normals to save, so it won't try.

Matt
Just because milk is white doesn't mean that clouds are made of milk.

Ashley

 Awesome, I totally overlooked that attr 8)

Cheers Matt   ;D