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The black line of legend
About Truespace Archives
These pages are a copy of the official truespace forums prior to their removal somewhere around 2011.
They are retained here for archive purposes only.
The black line of legend // Archive: Tech Forum
Post by weaveribm // Aug 6, 2007, 8:51am
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weaveribm
Total Posts: 592
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After conquering Glass reflections to get them showing in Vray-renders-from-Workspace there's just one problem left. Another just one :)
Window glass reflections are now working rendering from the Workspace side via the Vray Render icon. But in getting the glass reflections just right (low) suddenly there's a shadow thrown by where the edge of the window glass panes meets the hole in the wall that supports the window frame
I saw someone recommend using caustics and not transparent shadows but those two in any combination don't affect the unwanted shadow
The glass was very difficult to get right from Workspace side, please does this problem look familiar to anyone?
Peter
http://i117.photobucket.com/albums/o63/Mington/OnFinals/BlackEdgeToShadowSmall.jpg
http://i117.photobucket.com/albums/o63/Mington/OnFinals/BlackEdgeToShadowAaaggh1.jpg |
Post by chrisj // Aug 6, 2007, 10:09am
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chrisj
Total Posts: 239
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I've had problesm with glass, but I've not seen this one, however, here are some simple rules.
Make sure you use thin boxes, and not planes for glass windows, also, set to non shadow casting; this will not affect reflections. Caustics not required, just transparent shadows. You may also find it useful to drop the refractive index for thin glass sheets, as I've foudn some unnessessary distortion can occur.
Chris |
Post by Jack Edwards // Aug 6, 2007, 12:29pm
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Jack Edwards
Total Posts: 4062
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Could be because your ray depth is too low.
For GI renders this can be changed by setting the QMCDepth to a higher value.
-Jack. |
Post by weaveribm // Aug 7, 2007, 4:42am
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weaveribm
Total Posts: 592
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Thanks both!
Nothing helped I'm afraid this seems to be a very specific odd-combination and I entered a long spell whittling down the suspects (before coming back to thank you, while the blood was hot) and I think I've now sussed which part of the scene is to blame. Not the floor, window frames or the light
I moved the glass pane halfway-left and now the error-shadow shows the glass to be responsible perhaps, in the image below
On a hunch Columbo I pulled the glass pane into the (now empty) window opening, on the Y axis so that the glass was flush with the edge
Now the black edge becomes wider as the glass interacts with the wall/wall shadow proper, sometimes cancelling the light and sometimes allowing it to pass, quite predictably. The walls are just cubes with cutouts for the window frames they've always behaved normally before, no exotic materials
I've tried many many combinations of c-alpha, transparency and so on, nothing shifts the error-shadow. Images from Workspace/Vray Render
Thanks for support on this one. So very nearly there and aagghh! we've all been there. And will be again yes :)
Peter
Error-shadow now becomes wider on passing through more glass area
http://i117.photobucket.com/albums/o63/Mington/StrangeGlassInteraction1.jpg
http://i117.photobucket.com/albums/o63/Mington/StrangeGlassInteraction1_glassparam.jpg |
Post by chrisj // Aug 7, 2007, 5:24am
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chrisj
Total Posts: 239
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You shouldn't be using a transparency shader for glass. Could be the problem. Use the transparency setting in a reflectance shader. Glass IOR is around 1.5, and reflectivity aroun 4 or 5 percent.
That'll sort it. |
Post by prodigy // Aug 7, 2007, 5:32am
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prodigy
Total Posts: 3029
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Can you share the scene??
I mean... the specific part with the problem ;) |
Post by weaveribm // Aug 7, 2007, 6:24am
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weaveribm
Total Posts: 592
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Thanks Chris I'll look to do that after reporting what I think may be buglike behaviour... but I am using transparency there because nothing works. For completeness in case it helped. The three Vray transparency icons I only went there when I became desperate :)
The Vray Pure Glass material I've been using or else creating the glass in Modelspace
I've found now that I can have reflections in the Workspace/Vray glass but then there's the black edge. Or no black edge but then no reflections. There's definitely something weird going on with glass and/or reflections and/or Workspace-to-Modelspace switching
Starting again with notes for clarity on this repeatable feature?: I created a cube of default material in Modelspace then made it glass material, switched to Workspace and scaled it without changing any parameters, offered it up and so on in the shots below
The error shadow follows the glass material as I move the glass pane to the centre of the hole in the wall...
I'll build a test rig later in case something in my scene is causing this. I know very well that it could be me no worries :)
Thanks ever so much for support all!
Peter
Created a cube in Modelspace, reflectance glass
http://i117.photobucket.com/albums/o63/Mington/ErrorShadowNotes/ModelspaceGlassCube.jpg
Switched to Modelspace
http://i117.photobucket.com/albums/o63/Mington/ErrorShadowNotes/ModelspaceGlassCubeSwitchedToWorksp.jpg
Glass pane offered up. Glass not transparent in Workspace
http://i117.photobucket.com/albums/o63/Mington/ErrorShadowNotes/ModelspaceGlassCubeSwitchedToWor-1.jpg
Vray render looks ok although no reflections
http://i117.photobucket.com/albums/o63/Mington/ErrorShadowNotes/ModelspaceGlassCubeSwitchedToWor-2.jpg
Here's the problem. That shadow patch
http://i117.photobucket.com/albums/o63/Mington/ErrorShadowNotes/ModelspaceGlassCubeSwitchedToWor-3.jpg
Move the glass pane to the centre of the opening to probe the error
http://i117.photobucket.com/albums/o63/Mington/ErrorShadowNotes/GlassCentredInWindow.jpg
Now it's clear that the glass is responsible for the error-shadow
http://i117.photobucket.com/albums/o63/Mington/ErrorShadowNotes/ErrorShadowFollowsGlass.jpg |
Post by weaveribm // Aug 7, 2007, 6:38am
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weaveribm
Total Posts: 592
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Can you share the scene??
Yes of course Prodigy thank you!
I am sorry if it makes your head ache. Mine hurts too but I am loving working in Workspace and this takes the pain away :)
http://download.yousendit.com/889D41EF4B42EB49 (http://download.yousendit.com/889D41EF4B42EB49)
My Photobucket is at:-
http://s117.photobucket.com/albums/o63/Mington/
Peter |
Post by Vizu // Aug 7, 2007, 9:37am
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Vizu
Total Posts: 628
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http://wire-frame.de/trash/vray4.jpg
Same problem in Modeler side |
Post by chrisj // Aug 7, 2007, 1:19pm
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chrisj
Total Posts: 239
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glass is not correctly casting shadows, and caustics are not working. |
Post by chrisj // Aug 7, 2007, 1:26pm
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chrisj
Total Posts: 239
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checked the transparent shadows vray test scene supplied, and the glass candlestick doesn't cast a shadow. works OK in 7.1 with vray1.
looks like someone switched something off in the software. |
Post by chrisj // Aug 7, 2007, 1:31pm
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chrisj
Total Posts: 239
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regardez vous! |
Post by Vizu // Aug 7, 2007, 8:22pm
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Vizu
Total Posts: 628
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caustics in my scene is disabled.
The glass is disabled for shadows (object editor adwanced settings)
In my Picture i have the window with a rubber arround and the frame.
In the rendering it looks like the wall and windowframe is transparent but the windowrubber isn´t.
I show in my image only a area rendering in the center. |
Post by chrisj // Aug 7, 2007, 11:19pm
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chrisj
Total Posts: 239
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I checke weaveribm's scene in 7.1, and the artefact disappeared. problem is with vray1.5 |
Post by Vizu // Aug 8, 2007, 2:00am
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Vizu
Total Posts: 628
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seems like a problem for Caligar.
They have to fix this problem. |
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