 | | | Bump shading anomaly | Bump shading anomaly 2004-02-19 - By Pankhurst, Lawrence
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Hi Morten,
If you use a shadowmap on your light it seems to get rid of it! Even with
just a tiny bit of softness like 0.02, hope this helps, at 0 softness it's a
lot better but not gone!
Lawrence
-- --Original Message-- --
From: owner-xsi@(protected) [mailto:owner-xsi@(protected)]On Behalf Of
Morten Bartholdy
Sent: 19 February 2004 11:20
To: XSI@(protected)
Subject: Bump shading anomaly
Hi list,
I stumbled over this one because I worked on very high factor values for
bumps - check this image:
http://colorshopvfx.dk/XSI/bump_shading.jpg
<http://colorshopvfx.dk/XSI/bump_shading.jpg>
Notice the jagged shaded polygon edges where the arrows point. It looks like
the old Softimage renderer problem with raytraced shadows - here it is like
the shading is not smoothed when normals are pertubed by a bumpmap.
There is one pointlight in the scene with raytraced shadow and no area -
area lights will smoothen the problem areas but it is still there.
Obviously the jaggies correspond directly to edges so upping the SubD helps,
but still leaves the very hard edge between lit and shadow area. This kan
then be helped by using big area lights, but it sort of defeats the idea of
optimizing a scene for rendering.
It is not an on/off problem when the factor goes beyond a certain value - it
is just not very visible with low values, and certain types of bumpmaps
don't show it much either, which is why I have not seen it before.
Do anyone here know a workaround - a clever Rendertree solution to smoothing
the shading or is this one for support?
TIA!
Best Regards
Morten Bartholdy
3D Animator & Visual Effects Supervisor
Colorshop VFX
Denmark
.
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<DIV><SPAN class=390240713-19022004><FONT face=Arial color=#0000ff size=2>Hi
Morten,</FONT></SPAN></DIV>
<DIV><SPAN class=390240713-19022004><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=390240713-19022004><FONT face=Arial color=#0000ff size=2>If
you
use a shadowmap on your light it seems to get rid of it! Even with just a
tiny bit of softness like 0.02, hope this helps, at 0 softness it's a lot
better
but not gone!</FONT></SPAN></DIV>
<DIV><SPAN class=390240713-19022004><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=390240713-19022004><FONT face=Arial color=#0000ff
size=2>Lawrence</FONT></SPAN></DIV>
<BLOCKQUOTE>
<DIV class=OutlookMessageHeader dir=ltr align=left><FONT face=Tahoma
size=2>-- --Original Message-- --<BR><B>From:</B> owner-xsi@(protected)
[mailto:owner-xsi@(protected)]<B>On Behalf Of </B>Morten
Bartholdy<BR><B>Sent:</B> 19 February 2004 11:20<BR><B>To:</B>
XSI@(protected)<BR><B>Subject:</B> Bump shading anomaly<BR><BR></FONT></DIV>
<DIV><FONT face=Arial size=2>Hi list,</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>I stumbled over this one because I worked on
very
high factor values for bumps - check this image:</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2><A
href="http://colorshopvfx.dk/XSI/bump_shading.jpg">http://colorshopvfx.dk/XSI
/bump_shading.jpg</A></FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Notice the jagged shaded polygon edges where the
arrows point. It looks like the old Softimage renderer problem with raytraced
shadows - here it is like the shading is not smoothed when normals are
pertubed by a bumpmap.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>There is one pointlight in the scene with
raytraced shadow and no area - area lights will smoothen the problem areas
but
it is still there.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Obviously the jaggies correspond directly to
edges so upping the SubD helps, but still leaves the very hard edge between
lit and shadow area. This kan then be helped by using big area lights, but it
sort of defeats the idea of optimizing a scene for rendering.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>It is not an on/off problem when the factor goes
beyond a certain value - it is just not very visible with low values, and
certain types of bumpmaps don't show it much either, which is why I have not
seen it before.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Do anyone here know a workaround - a clever
Rendertree solution to smoothing the shading or is this one for
support?</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>TIA!</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Best Regards</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=Arial size=2>Morten Bartholdy<BR>3D Animator & Visual
Effects Supervisor<BR>Colorshop VFX<BR>Denmark</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV><FONT
size=3><BR><BR>.<BR></BLOCKQUOTE></FONT><FONT SIZE=3><BR>
<BR>
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Information in this email may be privileged, confidential and is <BR>
intended exclusively for the addressee. The views expressed may<BR>
not be official policy, but the personal views of the originator.<BR>
If you have received it in error, please notify the sender by return<BR>
e-mail and delete it from your system. You should not reproduce, <BR>
distribute, store, retransmit, use or disclose its contents to anyone.<BR>
<BR>
Please note we reserve the right to monitor all e-mail<BR>
communication through our internal and external networks.<BR>
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