Spotlight + Fluid - Jumping Shadows In Animation - Maya - Highend3d Artists Discussion Forums

We're sorry, but something went wrong.

Error: Backend Fetch Failure

We've been notified about this issue and we'll take a look at it shortly.

If you need to reach us, email support@highend3d.com

Dec 2006
1 / 10
Dec 2006
Dec 2006
slick
Dec '06

The scene:
I have a spotlight, a Cloud like Fluid (only Texture, no grid used ... e.g. like the StormyCloud example), a partiVol as atmosphere (tried fluid as atmosphere - doesn't match my goals) and a nurbs plane as ground. I animate the position of the light and texture time of the fluid. Rendering with Raytracing w/o scanline & w/o shadow maps (quite fast with good BSP settings).

Fluid: cast/receive shadows, shading quality 3, AdaptiveJittered, smooth, Depth max 8
Spotlight: Raytraced Shadows, no LightRadius (takes too long to render), 1 shadow ray, ray depth limit 4

Problem:
Rendering of some frames (even 3 would be enough to make visible the Jumping Shads) and animating them, the shadows from the clouds are jumping on the ground from frame to frame.

Troubleshooting

  • Removing the expressions for the light and fluid (so they are static during the frames) doesn't remove the problem. Shadows still jumping.
  • Increasing the Shading Quality of the Fluid or the raytracing settings in render settings (up to 5 5 10 8) doesn't help either

  • created

    Dec '06

  • last reply

    Dec '06
  • 9

    replies

  • 2.2k

    views

  • 1

    user

  • 2

    links

joojaa
Dec '06

Hmm where in the shading network is the expressionsas mr does not evel expressions that are inside a shading network or close into one. Aslo yo couldnt mekke very sane motionblr wth this setup.

Show s a small aniamtion sequence so we understand better what you mean by jumping.

slick
Dec '06

Hm, the clouds moving when I render with MR so I'm assuming the expression is recognized by MR. Here is the Shading Network of the expression. Also the grid-animated fluids, the field & the hair system of this scene are connected to the time1 Node.
http://galerie.tahun.de/displayimage.php?pos=-1022

Currently I can't make a video file here. Just five frames in a slideshow for comparison. Take heed of the shadows on the ground in front of the object in the center. (no comment to the impractical ground texture plz, i've changed it already )
What I forgot to say above ... the camera is translated, too.

Yes, with Motion Blur the render times increases about one order of magnitude, but I don't need it for this scene.

Btw, thx for the fast reply.
Btw 2, evel == evaluate?

joojaa
Dec '06

Well no thet expression isnt part of the shading network (however i suggets you bake out the expression as you may have problems batch rendering it), see what heppns is maya updates the value of origin X and it stays thatway untill maya updates the value on next frame. So even if you could motionblur the movement your not doing it because your animation is stepped in other words the clouds are stationary between the frames.

Do you mena the smal crawling dots? They look more like somekind of bias issue then anything else. BUt other then thet i cant realy se anything other thet woukdl be the the problem. If it s not a bias issue then its a issue of sampling.

slick
Dec '06

Thx for the hints on the expression!

No, I don't mean the flickering of the odd ground texture (right, thats a sampling prob, but I can't go further than 0 2 and contrast 0.05 for the animation). I mean the shadows - bigger dark areas - on the ground that "jumps" (change their position or disappear) from frame to frame. When I play it with 25fps the shadows on the ground and the partiVol do "flicker" (even if I use a one color ground texture). Too bad I can't show you a vid now.

slick
Dec '06

Figured it out (well, the reason, not the solution ). Global Illumation + moving Camera + Fluid shadows together with the ground photon map (needed to catch the emitted photons) causes the jumping shadows. If one of them is disabled (e.g. using a static camera) the shadow doesn't jump. Strange thing as I need all three of them. :confused:

joojaa
Dec '06

welll ye photon emission is random, just like fg so once you start doinfg something more complex the montecarlo routines strat to show up (because the end result varies dramaticaly form even small changes in randomness). The only sane thing to do is to use a cache, howvere it helps less than one can think so the only way is to increase the amount of photos emitted.

This si not a samplig problem but rather a stocastic one. Yor just randomizing stuff way too much. BUt just out of curiosity do you need photons at all?

PS you didnt mention you use photons that changes everything. but just incidentaly do you have a photon gartherer tarnsmat lane in fornt of your light?

slick
Dec '06

I'm using a photon map as cache (Rebuild photon map disabled) & I tried it without photon tracing, too. It actually works but with GI the lightning of the model is better. I don't use FG to save render time.

Thx for the hint to increase the amount of photons. I'll try it.

QUOTE(Joojaa @ 12/08/06, 09:35 AM) [snapback]254363[/snapback]
PS you didnt mention you use photons that changes everything. but just incidentaly do you have a photon gartherer tarnsmat lane in fornt of your light?
No, should I?

joojaa
Dec '06

Well i yor secens so simple teht you could omit photons alltogether and add soem fill lights to make the photon look and your rendertimes should drop too.

Sometimes the photon collector might help the solution to become a bit more focused- offcourse your ray length needs to be bigger, anwayt the pari woulume would like this especialy if you sue volume caustics.

slick
Dec '06

Thx for your effort! I added two non-photon lights to simulate the GI the photon emitting lights did. So I don't need photons any more.

Suggested Topics

Want to read more? Browse other topics in Maya or view latest topics.

Spotlight + Fluid - Jumping Shadows In Animation - Maya - Highend3d Artists Discussion Forums

We're sorry, but something went wrong.

Error: Backend Fetch Failure

We've been notified about this issue and we'll take a look at it shortly.

If you need to reach us, email support@highend3d.com