Bump problem

[Leandro Oliveira]

Hi Guys,

I´m using Softimage 7.5 with Gamma Correction turned on and Photographic Exposure as lens shader.

I think I don´t know how to use bump. As shown below, I applied a mia_material shader and the bump has no effect.



I have used many bump types, but no one took effect.

What is wrong?

Thanks,

[Hirazi Blue]

[first part of original post edited out]

If all else fails, you could, quite literally as a workaround , always plug the bump map directly into the Material node itself (the "orange node").

Important edit: the original remark concerning the "use old bump input" flag seems to be incorrect. Important edit: the original remark concerning the "use old bump input" flag seems to be incorrect. You'll have to plug the bump map into the standard bump port and set the mode to anything other then "use old bump input"

I've illustrated these two methods with a picture (and yes: one of the Shader balls is pasted in afterwards... ;) )

[Leandro Oliveira]

Thank you, very much, man!

I´ll correct this and I´ll make new tests.

Thanks, again.

[Leandro Oliveira]

Hirazi,

I made what you said and it worked very nice.

Thanks, bud.

[Rork]

From that fine manual, just sitting there on the HD

Bump Mapping

The bump parameter accepts a shader that perturbs the normal for bump mapping. This parameter is only used it the new bump_mode parameter is zero.

When no_diffuse_bump is off, the bumps apply to all shading components (diffuse, highlights, reflections, refractions... ). When it is on, bumps are applied to all component except the diffuse. This means bumps are seen in reflections, highlights, etc. but the diffuse shading shows no bumps. It is as if the materials diffuse surface is smooth, but covered by a bumpy lacquer coating.

In mia_material_x there are also three new parameters related to bump mapping: two vector bump inputs, overall_bump and standard_bump, and a bump_mode parameter defining the coordinate-space of those vectors. The shaders put into overall_bump or standard_bump should return a vector, but it is also legal for those shaders to modify the normal vector themselves and return (0,0,0).

overall_bump defines an overall bump that always applies both to the diffuse and the specular component at all times, regardless of the setting of no_diffuse_bump standard_bump is a vector equivalent of the old bump parameter, in that it applies globally when no_diffuse_bump is off, and only to the specular/reflection "layer" when no_diffuse_bump is on. However, the standard_bump is added "on top of" the overall_bump result.

The intended use is to put the mia_roundcorners shader in overall_bump and your normal bump shader into standard_bump. This way, the "round corners" effect will apply both to the diffuse and specular component irregardless of the setting of no_diffuse_bump.

The bump_mode parameter defines the coordinate space of the vectors, and if they are additive or not. The following values are legal:

* 0: compatible mode. The old bump parameter is used in place of overall_bump and standard_bump.
* 1: "add" mode in "internal" space
* 2: "add" mode in world space
* 3: "add" mode in object space
* 4: "add" mode in camera space
* 5: "set" mode in "internal" space
* 6: "set" mode in world space
* 7: "set" mode in object space
* 8: "set" mode in camera space

The "add" modes mean that the vector should contain a normal perturbation, i.e. a modification that is "added" to the current normal. Whereas "set" mode means that the actual normal is replaced by the incoming vector, interpreted in the aforementioned coordinate space.

This new scheme makes the mia_material_x bump mapping compatible with more mental ray integrations, as well as allows the round corners to be applied even if no_diffuse_bump is on.

Yup, it looks confusing at first, but it makes sense after a while. Not to say bumpmapping in Softimage is way too complicated for my taste.....

rob

[Hirazi Blue]

Wow, that must be one of the lengthiest RTFMs I ever did see (even if it wasn't intended that way)... ;)

[Rork]

No, it wasn't intended to be long

But mentioning the fact that there's a ton of information on your HD about MR isn't a bad thing, right??

rob