OTOY Forums

Hi,
I was wondering if triplanar projection is supported with bump? It seems that it does something with very high values but the projection seems incorrect through the bump. (diffuse works fine)
(latest build 3.06.0.4)
Thanks
Yaniv

WhyGee wrote:Hi,
I was wondering if triplanar projection is supported with bump? It seems that it does something with very high values but the projection seems incorrect through the bump. (diffuse works fine)
(latest build 3.06.0.4)
Thanks
Yaniv

I can't say for the Houdini plugin,
but in Octane Core 3.06, bump texture with triplanar projection is supported and works perfectly .

It can be a problem already fixed in the final Octane 3.06 core. I want to release a new plugin build with this core this week, but if you want to share a sample scene with this problem, I could test it here with it to be sure.

Thanks,
-Juanjo

Hi,
I've attached a sample scene with 2 renders.
It's not that bump doesn't work, it's that it seems like the triplanar projection (connected to diffuse) is sampling the normals after the bump is applied. I could see why this may be useful in some situations but usually I wouldn't expect the texture to change because of the bump. It would be nice if it was an option on the triplanar node and not the default behavior.

Thank you
Yaniv

I've also done another test where I bake out a triplanar projection. comparing the triplanar projection and the resulting baked texture, in the diffuse channel they look the same. When connected to bump, they behave differently, aside from giving a different bump look, the triplanar requires multiplying the intensity by factors of tens.

OK, yes, I can see the problem now. As you say, it seems an Octane limitation, that is computing the triplanar mapping using the shading normal before it has been perturbed by the bump or normal maps. I'll ask the Octane developers about this feature.

Thanks,
-Juanjo

WhyGee wrote:Hi,
I've attached a sample scene with 2 renders.
It's not that bump doesn't work, it's that it seems like the triplanar projection (connected to diffuse) is sampling the normals after the bump is applied. I could see why this may be useful in some situations but usually I wouldn't expect the texture to change because of the bump. It would be nice if it was an option on the triplanar node and not the default behavior.

Thank you
Yaniv

Yes, that seems to be an oversight. The box projection also uses the interpolated geometry normal and not the bump mapped normal. We will change the tri-planar texture node to use the interpolated geometry normal, too, unless there is a very good reason to make it optional, in which case we could make it selectable.

the option to have it as is is not something I see a real use for other than just a variation on how the texture is sampled but maybe someone will find it useful. Normally that is definitely not the desired effect.

Thank you!
Yaniv