CompuServe Thread

#Stripes and flickers

7 messages in this thread
#162644From: Chris JohnstonApr 3, 1995 10:16 PM
I'm working on a large project (It fills my 32 MB of RAM and uses about 30 MB of swap file) and I've noticed two things. On the outside of my building I've got two dark stripes that seem to follow the edge of a face that goes from the top of a window to the top corner of the wall. I can't see a gap between the faces but that is sure what it looks like (Incidentally, I've had a lot more wierd problems with boolean subtracts than I used to with earlier versions – sometimes missing faces and sometimes extra faces) I can't see the dark stripe unless mapping is on (I'm using a brick map). Flat shading and mapping off and the stripe disappears. Raytraced shadows/mapped shadows seems to have no effect. I've got a similar bright stripe on the other end of the wall… I've also got a ***lot*** of flicker in some of my semi-shadowed areas as I move the camera. Any ideas? Chris – Chris Johnston, Written 03-Apr-1995 @ 22:16:42 Using: Windows NavCIS PRO 1.6
#162692From: Robert C. RitgerApr 4, 1995 1:30 AM
Chris: Was your large project imported to 3DS from a .dxf file? I've had most of the problems you have described with geometry created in a CADD package and then imported. You could mess around with welding vertices but you may try the opposite approach if you have rectilinear geometry – Detach Faces. I had faces flickering and these strange fading triangular voids which all became normal when I detached the faces (Your dark stripe may be similar to this). This leads me to believe that my problems were in the smoothing groups assigned and/or the weld threshold used during import. Detaching the faces was the fastest way to an answer but perhaps not the most elegant or efficient for rendering. Bob
#162919From: Chris JohnstonApr 4, 1995 9:49 PM
Bob: Interesting idea… I did a lot of the original drawing in Autocad and did have a lot of trouble with the DXF import – missing and flipped faces, etc. Visual link didn't work either – all it imported was the layer with the doors on it! I don't remember whether these features are things that were modeled in Autocad or things that I rebuilt in the shaper and lofter. Chris – Chris Johnston, Written 04-Apr-1995 @ 21:14:15 Using: Windows NavCIS PRO 1.6
#163179From: John K. JordanApr 6, 1995 12:15 AM
>>stripe, window to corner… I hope you have this fixed by now, but here's my 2 cents… My latest encounter with window/wall stripes was just today. <g> In my experience, this is almost always caused by a thin sliver of a face. These used to cause me a lot of grief, but I can usually fix them in about 30 sec. now. Look at the ends of "edge" of the face carefully and make sure the edge is not actually more than one face. Sometimes a boolean will leave very thin faces that confuse the smoothing algorithms. Try Select/Face/Single or Mod/Vertex/Move (watch the rubber-band lines) to track down a rogue face. Also, increasing the weld threshold, then selecting all the vertices in the area and welding "Selected" should zap any errant face slivers. Also, if you've done any manual vertex editing on the wall, you may have inadvertently "folded" a face over another, resulting in a discontinuity. In this case, the Edge/Turn command can usually repair the object. JKJ
#163582From: Chris JohnstonApr 7, 1995 7:50 PM
Thanks, I'll go look at the mesh again. I suspect that this is an artifact of a boolean operation, either in 3DS or AutoCad since it shows up in exaclty the same position on both the first and second floor. I'll go hide everything but those walls and go play with it again. Chris – Chris Johnston, Written 07-Apr-1995 @ 20:37:56 Using: Windows NavCIS PRO 1.6
#163883From: Mark G. BrowningApr 10, 1995 8:10 AM
Are you network rendering? We have had a lot of problems with stripes and flickering. We traced it down to edited material mappings on a local station different than the network versions of these materials. Every tenth frame or so, the frames rendered on the one machine, would flicker. When we made sure all the paths were open to just one material map directory all the problems went away.
#164015From: Chris JohnstonApr 10, 1995 8:39 PM
Mark: I've tried to copy all of the texture maps around to all of the net machines, but I couldn't swear that the flicker dosen't follow one machine or another. I'll have to look at the individual frames and see if I can make any sense out of it. If it flashes on every other frame it probably isn't the related to network rendering, since my Pentium machine is about half as fast at the 486 (the 486 has twice as much memory) Thanks, Chris – Chris Johnston, Written 10-Apr-1995 @ 21:18:17 Using: Windows NavCIS PRO 1.6