Deep shadow map tests

Here are some test I made of the DSM build. I had 170 000 hairs on my original head. I lowered this to about 50 000 and did a very rough comb I was a bit eager to test this out and it was bombing out with the original number of hairs I had.

I have three lights in my scene all spots with shadow buffer of 512 and a bias of 0.2 the only difference was I set one group of lights to classic of the shadow buffer and the others at deep.

render times for the classical buffer was 24:11.59 and for the deep shadow buffer was 45:47.69

the lights behave differently in terms of the saturations I get out of my renders.

you can read up more on DSM and find a link to a build by visiting this thread:

feel free to post any test you conduct into this thread I would love to see what other users come up with, my next test is to see how this handles transparent shadows something regular shadow buffers can’t do.


Interesting. The DSM one is better, but it’s quite long to render.
When you’ll have the time, could you test the same scene with Ray shadows?

Here is the same scene with ray traced shadows, it times of finish it probably the worst in my view, but than again I have not quiet got the hang of lighting strands with ray traced shadows. Plus I couldn’t really tweak or move things about so as to standardize the test.
the render time was 26:57.11

In terms of finish I lean towards the DSM render, though not been able to work with the same number of strands as I orignally did and not been able to build duplivert arrays with my spots, something I always do, is a bit of a let down.


Really cool render, btw :slight_smile:

Yeah DSM fits into its own niche in the lighting toolset. It’s for strands and volumetrics, really, and because of its speed it doesn’t seem too useful if you use more then 2 or 3 lamps with it (though my code does support multithreading).

Also I’ve not yet gotten soft shadows to work with DSM; once I get something working there it’ll hopefully be more useful on its own.

I think using DSM spots as only shadow lamps to shadow specific things that need it (hair, whatever) might be a good idea, though that’s being buggy at the moment, need to fix it.


The strand renderer doesn’t work with raytracing - it won’t appear to reflections, refractions, raytraced AO or raytraced shadows. What you’re seeing there are no shadows at all. In order to use raytraced shadows, you have to use geometry hair (unclick strand render button in particles).

thanks for the info Broken, I light mostly with buffer shadows so I was not fully aware that strand renderer doesn’t work with ray tracing, I was taken aback with the lack of self shadowing but didn’t have a clue as to what was wrong, I will post another render when I get the time.

You can also try the Irregular shadow buffer option, it basically does the same thing as ray tracing (only iirc it doesn’t support transparency properly, or something like that). Not sure if it’s worth it or not.


I’m wondering two things:

  1. Why this simple render takes almost 1/2 an hour with just regular buffered shadows. That’s nutty. System specs?
  2. Why your base model has 10x the amount of hairs on a real person? 130k-200k is all you need. If you can’t get it to look right with that amount, then something else is off somewhere.

I will recheck the number of hairs again, but the render time could be due to my sucky laptop, its celeron, that I work on. I don’t animate so as long as renders are coming out in decent amount of time I am not too worried but than my render times were not too extraordinary some other users in the blending life contest reported times way longer than mine.

P.S Doh! it seems the old brain has gone on vacation I had 1000 parent hairs and 170 child hairs giving my a grand total of 170 000 hairs. I cut this down to about 50 000 hairs to get a render out of the DSM. Reading what renderdemon has written it seems that a large amount of hair and DSM don’t go together. What would be interesting would be if someone render the chinchilla from BBB. I have a copy of the blend that was given away with the 3D world issue 106 but with my current hardware limitations I won’t attempt anything cause following that tutorial I ended up with a character with about 250K of hair particle and this is a cut down version of what was used in the movie.

I don’t even know what deep shadow maps are. There were no links for info in the build on graphical.