Shadow Pass?

Hi All
Don’t know how many of you have had a chance to play with the render passes, but I for one jumped right in!

I have a question for anyone who has had a tinker:
I thougth that a shadow pass was a render of the shadows only, controlled by an alpha channel for transparency. Thge shadow pass in the CVS builds have colours and geometry in them and no alpha.

I get a shadow only pass normally by setting the casting objects material only to cast shadows, and the receiving objects material to be see-through (with the env button i think), and this produces exactly what I want.

I understand how to multiply the diffuse and shadow passes together to re-build the render, but I don’t know how much use this type of shadow pass (if that’s what it is) would be in compositing live action and CG, which is usually the point of rendering in passes.

Any suggestions?


I played with this for a while and the colors don’t matter. As long as you use one of the darker blendding modes your shadows are going to look like shadows. Render to seperate passes, upload into photoshop, gimp or as images in the nodes editor and play with the different blending modes. Render passes give us more creative controll so if you play with the other, lighter blending modes you can get some cool effects that are otherwise not attainable via the normal render pipeline. The colors seem to be negatives-or some such, of the colors used within the scene and are, as far as the experiments that I’ve performed up to this point, totally undetectable when multiplyed over the color pass. The geometry isn’t geometry from what I’ve seen, only planar intersections of these negative colors (or whatever they are).

Get creative with it and see what you can come up with. I like what I’ve seen so far…except for the fact that it is all too easy to crash the pipeline if you’re not careful about what you do. Enabling a uv pass without a uv map loaded will bring it down every time on the build that I’m using.

RamboBaby: You can help the developers by reporting any crashes you have. Remember to include a test .blend to make confirming them easier.You can do this at the bug tracker.

You need to create an account to report bugs by the way.

There have been a lot of times that I’ve wanted to report bugs, but the devs get understandably anoyed if you don’t do good research and report a known issue. I know they’re very busy, heck - just look at the phenominal rate at which Blender is developing. I probably will start reporting soon cuz my skills are finally starting to get up to snuff in many of the areas that intrest me in this program. I’m not sure that what I posted above is a bug per-se, I think it’s what they call an unhandled exception. I just wasn’t thinking (I’m good at that) when I enabled the button. My scene didn’t have a single uv map in it, though it took me a while to track down the source of the crashes. Quite a bit of the logic in the nodes compositor seems fairly rigid at this point, but I’m sure it will become much more flexible in the near future.

Blender should not crash in any case. If it crashes, it can be considered a bug. :slight_smile:

The issues will be taken a look at. The more the users report bugs, the cleaner releases we will have. We do our best to yield best possible quality.

Huh? This is what I get with a simple scene rendering with shadow linked directly to composite.

Looks like a mask/shadow to me?

Edit: I just noticed the shadow on the cube disappeared? In my first render I forgot to turn on ray-shadows in my lamp and I got just the self-shading, now it’s gone though…