soft shadows

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  10 October 2003
soft shadows

I have rendered a 5m x 0.8m shop sign that has extruded text. It looks great except for the shadows which have hard edges and look unrealistic. I read the manual and its says spotlights and distant lights use raytraced shadows which have hard edges. It mentions something about using shadowsmaps for a soft edge but shadow maps dont behave well with transparancy. Only area lights cast "true" shadows, but they have a horrible grainy appearance and mess up the rest of the render.

Does anyone know how to render realistic shadows.

Thanks in advance
  10 October 2003
You have to increase the quality level of the area light to 4 or 5, also increase your AA passes.

If that doesn't work for you, try Shadow Designer.
  10 October 2003
Turning on Shading noise reduction usually helps.

WIP Skaven, Rat Warrior
  10 October 2003
Quote: Originally posted by Tottebias
Turning on Shading noise reduction usually helps.

Yes, but be carefull as it also softens bump maps!
  10 October 2003
Though i probably sound like a broken record... i suggest learning the spinning light technique.

There's a thread about it on this forum... wait a sec...
  10 October 2003
thanks for the input.

Im rendering some tests now, using different techniques. radiosity (had to give it a shot and see) is taking forever!

will post the results when done
  10 October 2003

distant light enhanced low AA raytraced shadows - original render

quality 5 area light enhanced low AA raytraced shadows

quality 5 area light enhanced low AA raytraced shadows with radiosity

the last two are better, but they still dont look 100% right to me.
  10 October 2003
Spinning lights - using my Overcaster setups
Attached Images
File Type: jpg spinning.jpg (12.9 KB, 69 views)
  10 October 2003

one spotlight spinning from -360 frame 0 to 360 frame 2
frame 1 rendered
raytraced shadows
motionblur on set to 120% dithered.

Thanks for the thread link. It is worth a try, but I dont understand this spinning light theory. It seems to darken and dirty the render. Would a much larger area light be the answer, or maybe multiple spotlights. In real life shadows are gradual because the light source is scattered and large (in the case of sunlight). Any ideas?
  10 October 2003
Have you ever tried to use shadow maps of high definition (3000x3000)
  10 October 2003
The spinning lights don't darken or anything like that. There seems to be something wrong in the way you set up your rig... at least, the amount of spinning is wrong. If you e-mail me the scrnr / objects, i can have a closer look for you -

The trick simply uses LW's way of calculation motion blur to make a single light to appear to shine from multiple points.

Here's more reading...

Another thread

The "original" spinning light tutorial

Last edited by Halsu : 10 October 2003 at 01:28 PM.
  10 October 2003

The reason your area light shadows are so hard and crisp is either that your area light is far away or that is is very small relative to the logo.

Try to move it closer or to size up the area light (using the size tool).
  10 October 2003
Still no luck with spinning lights. Tried various movement ranges but the effect is not there, although the amount of "dirt" does vary. Will keep trying, I am intrigued by the principle.

pixelranger, that did the trick. scaled area light to 6 on x and y, and now I'm getting the results I expect. Fine tuning needed, but on the right road.
  01 January 2006
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