Results 1 to 4 of 4

Thread: Shadow results: need advice.

  1. #1
    AeroAnimator 4dartist's Avatar
    Join Date
    Feb 2003
    Location
    Chattanooga, TN
    Posts
    1,065

    Unhappy Shadow results: need advice.

    I can't figure out if this is looking correct. Those arrow shaped shadows are bugging the crap out of me. Is it just because thats the actual surface contour and the shadows are just exposing it? Or is that an error?

    The object was originally displaced with an image. It had the same results, then I saved the transformed object, hoping it was a displacement problem, but same shadows. The renders here show an empty scene except for the 'save transformation' object and 1 distant light. Raytrace shadows.

    I tried a point light, spot light, and even shadow maps. The same results. Do i just need to crank the tessilation on the original displacement?? The first render is single sided, and just to see what would happen I made the object double sided (shown in the second image) Odd results. The light is just at an 11° angle, so not below the surface at all.

    Thanks for any advice...




  2. #2
    Unregistered Guest Sarford's Avatar
    Join Date
    Feb 2006
    Location
    Amsterdam
    Posts
    1,187
    I think the second image looks pretty acurate. If you look at the three triangles in the lower left corner, you'll see them too in the wire.
    Objects with surface normals on just one side give problems with shadows, so making them double sided is better.
    I would keep the original mesh a sub-D mesh (double sided) and up the resolution of the displacement.
    MacBook Pro quad core 2,6Ghz, 8Gb ram
    Mac Pro dual Intel quad core 2.8 Ghz, 8Gb ram, Quadro 4000

    my website and 2011 showreel
    http://www.simonglas.net

  3. #3
    Engineer/Entrepreneur Sekhar's Avatar
    Join Date
    Sep 2005
    Location
    Pasadena, CA
    Posts
    2,124
    Spot light with shadow map would work, except increase shadow fuzziness.

  4. #4
    AeroAnimator 4dartist's Avatar
    Join Date
    Feb 2003
    Location
    Chattanooga, TN
    Posts
    1,065
    Sekhar- Ya shadow map helps because the sharp points sorta fuz out, but still pretty undesirable because I'm aiming for pretty sharp shadows. But in a pinch I think that could help for sure.

    Sarford- I sorta see what you mean. I've found toggling d-sided can sometimes fix problems you are having, and sometimes it is the problem hehe. You were right about cranking the tessilation amount. I took the transformed model and just hit sub-d on it, (making poly count from 12 thousand to 1.2 million) The results were more or less flawless. The shadows didn't show any artifacts. Lesson learned i guess. If light is cast near the tangent to a lower poly density surface you run the risk of these type errors. The solution is to increase poly count of the surface by a lot.

    Thanks for the ideas guys.

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •