RT shadows...or not?

#1

I’ve been thrashing about in EI and various modelling apps to find pipelines for working and to see what I can do that’s familiar to me. Trying raytraced shadows seems to be a bit of a ‘no no’ as the hard traced shadows are too sharp and the soft RT shadows take far far too long on the type of scene I envisage. So I’ve found still using the phong rendered shadow maps seem to be the best bet- but a biggish map (5000 x 4000) is needed, although they render pretty quick. They seem quite sharp and soften off at the ends!
Anyone got any views on this? (Link to ‘exterior’ image)

http://www.martinkay-3d.com/EI_pages/outside.html

Martin K

#2

Hey! That’s very Daliesk.

Soft raytraced shadows are a little slow but usuable.

Here are some steps.

Use optimize toggle.
Only use as many samples as really needed.
Turn off ‘cast shadows’ in your large ground plane.

There are a few more I’m sure I’ll think of but that’s enough for a bit of a start…and alwasy turn off AA for initial render tests with soft raytraced shadows.

Paul

#3

Thanks Paul, I’ll try that.

Martin K

#4

Just one additional tip off the top of my head;

Only use spotlights for RT soft shadows, look through the light and adjust the inner and outer cones until they only just contain your scene. This will focus the rays.

It makes the rendering a wee bit faster,
Ian

#5

Hello gentlemen

True, but maybe it’s better to say: RT soft shadows are very slow but very usable :slight_smile: A few more comments/advices:

  • “optimize shadow generation” = 5-6 times faster. Unfortunately, it creates moire artifacts enough often;

  • necessary count of samples depends also from light’s radius (larger radius requires more samples)

  • more tangent (to surface) direction of soft shadow light is preferable, less rays are required

  • turning AA OFF for all tests is a “rule number one” if any RT feature is in use , count soft shadows (no matter they are not RT anti-aliased)

  • soft shadows and RT translucency (known also as SSS) are good friends, they help each another

#6

Thanks for all the pointers! One thing I’ve found is rendering twice size and reducing down helps get rid of the jaggedness at the sharp end of the shadow.

http://www.martinkay-3d.com/EI_pages/lighting.html

Martin K

#7

I seem to remember a whole load of Paul’s RT softshadow tips being cut/paste from postforum straight into the EIAS 6 or 6.5 pdf manual, take a look… RT shadows are worth the “cost” IMO, don’t care much for shadow maps anymore…

R

#8

I didn’t realize that. I hope they were good tips:-)

Paul

#9

Of course they were good!

Hey Paul, how’s it going? Good to see you on the boards again.

.

#10

Thanks:-)…going good.

#11

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