Hi Hisashi, so the "Scale output units to meters" option only controls scaling of objects and does not change anything about materials. But it's a scaling that is applied directly to vertices not to an object's transform so I guess it is similar to doing the scale while in vertex mode in Modo.

The moire artifacts you are showing there look like a type of either z-fighting or self shadowing artifact. These types of render artifacts can be caused by raytracing where when the ray is fired out the start of the ray is too close to the surface and it ends up hitting the same surface it originated from, or also if there is a duplicate surface or other surface very close by. There is usually a "bias" factor option that can be edited to avoid this.

Most likely when you do the scaling in Item mode, the bias factor is being scaled along with the object, that's why you see a difference when you have done the scaling separately.

You should be able to fix the problem with the MoI "Scale output units to Meters" if you also adjust that bias factor to be better suited to the size of the object, those particular types of render parameters like bias factors are sensitive to the numeric size of an object and may need to be adjusted if your objects are of some different size than what the default settings expected.

Hope that makes sense. I'm not all that closely familiar with Modo myself so I'm not sure exactly where you go to adjust the bias factor, you may want to post on the Luxology forum for help with that.

But I have just double checked the code to make certain that the "Scale output units to meters" option in MoI only controls a scale factor applied to vertex positions and that's all that it does, not any changes to materials. It's just that some types of rendering especially raytracing of shadows or transparent materials are sensitive to bias factors which are size dependent and may need to be adjusted for objects which have a different size than what the default values are set to work for.

It also may be easier to do your work in Modo at the scale that the default render settings are tuned for rather than one much larger or smaller.

- Michael