soft shadows

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Old 10 October 2003   #1
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
Old 10 October 2003   #2
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.
Old 10 October 2003   #3
Turning on Shading noise reduction usually helps.

WIP Skaven, Rat Warrior
Old 10 October 2003   #4
Quote: Originally posted by Tottebias
Turning on Shading noise reduction usually helps.

Yes, but be carefull as it also softens bump maps!
Old 10 October 2003   #5
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...
Old 10 October 2003   #6
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
Old 10 October 2003   #7

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.
Old 10 October 2003   #8
Spinning lights - using my Overcaster setups
Attached Images
File Type: jpg spinning.jpg (12.9 KB, 69 views)
Old 10 October 2003   #9

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?
Old 10 October 2003   #10
Have you ever tried to use shadow maps of high definition (3000x3000)
Old 10 October 2003   #11
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.
Old 10 October 2003   #12

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).
Old 10 October 2003   #13
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.
Old 01 January 2006   #14
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