What value should I set for Export Scale parameter in the rendering settings?

[numan85]

I am using C4DtoA version 2.4.0

I am little confused by this parameter "Export Scale" in the rendering settings. The docs mention the default value is .01 but for me it is 1 meter...

So my specific question is if in my C4D projecting settings I have "Project Scale" set to .1 mm what value should I set for the "Export Scale" parameter in the render settings?

[peter.horvath6V6K3]

The Project Scale in Cinema 4D defines what the values mean when it comes to length units. So let's say you have a Cube of Size 100 in your scene. When you set the Project Scale to 1 mm, it means that the Cube size is 100 mm.

The Export Scale tells how you want to translate this value to Arnold units, so basically it means what 1 Arnold unit represents. If you set the Export Scale to 1 meter, then the Cube size is 0.1 in Arnold. If you set it to 1 mm, then you have 100 in Arnold.

There are a couple of length unit dependent parameters in Arnold, for instance the light falloff, volume density, etc. Changing the scale can affect them. Some parameters are adjusted automatically by the plugin (e.g. light intensity), some are not. For instance if you scale down a volume then you have to scale up the density in the standard_volume shader to get the same result.

Normally the default 1 meter Export Scale is fine. If you work with low scales you might need to lower the export scale to avoid precision or clipping issues, like here.

[numan85]

So Peter, to avoid any clipping issues should I set "Export scale" to 0.1mm (to match the "Project scale" of 0.1mm)?

[peter.horvath6V6K3 · Accepted solution]

Yes, that should work. If you have any trouble with it, just let me know.