I have been trying something for a while but no luck. Sometimes after rendering all my passes together, there are mistakes in some passes, for example the depth pass. When I render only the depth pass, I unclick the regular image and the rest of the pass but , C4D still spend the same amount of time to calculate this "background" pass and rendering the dpeth pass. I would like to calculate only the depth pass and render it, without calculating the whole image.
I attached screenshots of what I mean.
In the first picture, you could see even after doing what you said, still is calculating the image ( besides the GI) , in the second, if you select the Single pass option to preview , you could see the "background pass" I was talking about it that has been calculated. In the third one, you could see that the depth pass has been calculated too.
I don't think you can render only the depth pass (at least from a calculation standpoint) but you can turn off GI, Shadows, Textures, Transparency, etc. etc. in Render Settings and Render Settings/Options as they have nothing to do with the depth pass which should make it much quicker.
it is actually a shame , because put down a little the process of the multipasses. Specially if you want to modify your reflections and do only the reflections part without calculating the rest. I guess something Maxon has to improve.