In Daz studio 4 you can change a individual lights illumination to diffuse only or specular only, how do you do this in Carrara?
any help would be appreciated
There is no such thing a specular light and /or diffuse light in the real world
these are properties of the object / material and its Highlight and Shininess strengths or maps.
if you want objects glossy or dull in a specific areas you can create a grey-scale image and add it to the shininess
hope it helps :)
You can't. Carrara's specularity is controlled in the shader of the object, not the light. This is a fundamental difference in Poser/DS and most of the rest of the 3D world...
If you have PRO you can render out separate Multi-Pass layers for Diffuse and Specularity.
HDRI / Image-based Lighting (IBL) creates non-directional light without specularity. (any of the Global Illumination options on their own generally do not create specularity, I believe)
You can control specularity in each shader. It is a 2-channel control the first called HIGHLIGHT which controls the color and pattern and uses the UV map (if you have a specular map put it here).... The second channel is called SHININESS and it is a single value (best controlled with a VALUE 0-100 shader) that focuses the specularity according to the angle of the light. Lower numbers spread the specularity across the object, higher values focus the specularity to a narrow angle.... I have a video tutorial on my website called "Creating Skin Specularity" or similar... Link to my site is in my sig below...
Shaders Plus appears to have this feature.
Holly's video tute on specularity is highly recommended along with her other tutes! :)