Deep shadow maps make no sense to me...

CypherFOX

Greetings,
I just turned off deep shadow maps (changed to rendered shadows) on five lights in a scene (based on Merlin's Monument) and the render time went from 54 minutes 25 seconds to 15 minute 52 seconds.

This matches something I've consistently noticed; deep shadow maps are significantly slower than rendered shadows.

This is completely counterintuitive. Why would you ever use DSMs? What am I missing...?

Thanks muchly for any insights!

-- Morgan

Richard Haseltine

DSMs used to be at least a little faster, but ray-traced shadows have been greatly improved in recent iterations of 3Delight. The relative speed also depends on what is in the scene - in general, the more transparency maps there are the slower ray-traced shadows get while DSMs are fairly constant (using lights with a fixed falloff, though unrealistic, can help with that as you don't get the renderer processing lights that have long-since dimmed to the point of invisibility. I remember using Lisa's - or was it Laurie's? - Toadstool lane house with several point lights in the lamps, and a tree full of transmapped leaves - it would have taken, I think, the best part of a day to render while using uberPoint and setting a sensible fall-off, so that most lights didn't reach the tree, enormously speeded the process - DSMs weren't an option as they have never been available for point lights).

SickleYield

I never use Deep Shadow Maps for that exact reason, Cypher. Haven't since DS3.

LeatherGryphon

Actually I often use Deep Shadow Maps specifically for the look that they give. Some scenes benefit from the grainy atmosphere of DSM. Dark scenes, mystery scenes, fantasy scenes, dark, mysterious, woodsy, fantasy. Some of my favorite themes. However, I'm not wedded to DSM. There are times that I use ray-traced shadows when I want to brighten up or want more detail or to lighten the mood.

But my experience with DSM vs ray-traced shadows is that DSM is much faster. When I do a ray-traced scene I go make dinner while it's rendering whereas I can complete a 1920x1280 DSM scene in 30 or 40 seconds.

Ghosty12

I rarely use DSM's if at all, I use Raytraced shadows because I am after deeper better looking shadows.. And since recently found that increasing the shadow softness to about 90 to 95% makes the shadows much softer but still distinct..

The one thing I am hoping for to be hard coded into a future release of Daz Studio is indirect lighting or IDL for short.. I have Poser Pro 2014 and the major difference IDL can make to a scene is incredible..

I know there are addons for Studio that allow you to do IDL but the cost of them is what stops me from buying them.. Because the good thing about Poser is that IDL is built into the software as standard and all you do is turn it on with the tick of a box and well it does the rest..

I would like to see something like that in Studio and well I would use it more since I am using Genesis is much better in Studio than Poser but due to Studio not having IDL hard coded then well you know the rest.. :)

Richard Haseltine

uberEnvironment has IDL.Use the Environment Mode option (in the Lighting group in Parameters with the light selected).

Ghosty12

Richard Haseltine said:

uberEnvironment has IDL.Use the Environment Mode option (in the Lighting group in Parameters with the light selected).

Ahh k thank you.. But is there a way to stop it from removing my spotlights, and well after playing around with it well mmm yeah, .for me at least it is not user friendly.. The main problem is that any lights added are then removed and well I end up with poor results and do not get the effect that I want..

Might play around with it more later but not at the moment just way too much fiddling around..

Richard Haseltine

Hold down the cmd(Mac)/ctrl(Win) key when loading the environment light and choose the Add option.

CypherFOX

Greetings,

LeatherGryphon said:

But my experience with DSM vs ray-traced shadows is that DSM is much faster. When I do a ray-traced scene I go make dinner while it's rendering whereas I can complete a 1920x1280 DSM scene in 30 or 40 seconds.

This is what confuses me... I just rendered an image, 512x384, and it took 1 minute 53 seconds with raytraced shadows.

I then rendered the same image with the four distant lights (provided by Merlin's monument) converted back to Deep Shadow Maps, with a Pixel Samples of 32 for each of X and Y in Render Settings (which is what it usually is for me). I timed it using a stopwatch app, and for each of the distant lights I got:

Light 1: 1m7s
Light 2: 1m14s
Light 3: 1m1s
Light 4: 1m17s

Total render time was 6m6s, more than 3x as long as the prior image.

If I reduce the Pixel Samples down to (e.g.) 4, the DSM creation takes significantly less time, so I'm guessing you're running with a lot lower pixel samples? Of course if I run with equally low pixel samples for raytraced shadows on a 1920x1080 shot from the same scene I was rendering above, Raytraced shadows are still around 12 seconds faster. (3m31s DSM vs. 3m18s Raytraced.)

This has been valuable for me, if nothing else to realize that I can significantly drop the pixel samples to do more efficient first-pass renders.

-- Morgan

Ghosty12

Richard Haseltine said:

Hold down the cmd(Mac)/ctrl(Win) key when loading the environment light and choose the Add option.

Thank you for the info it worked a treat didn't know about using ctrl for adding never used it before.. :)