View Full Version : geometry display fragmentation

06-19-2008, 04:28 AM
I'm having this display problem with a model of a building.

When I go into polygon mode the polys and edges look corrupted.
It makes it impossible to accurately observe the changes I make.

Here's a screen grab of it:http://home.comcast.net/~b.ballerin/imagez/display.fragmentation.jpg

It just happened all of the sudden.
I left the computer for maybe a half hour and left cinema open.
When I came back and started to work it was like this.

I thought maybe the screen just failed to update right as this has a tendency to happen.
Switching views forces the display to update and fixes the corruption.

Well, not this time.

I closed and reopened cinema and when I entered poly mode it was still corrupted.
So I restarted the computer and after that it was still corrupted.

I switched off enhanced openGL, restarted cinema, still corrupted.
I tried a couple options in the display editor, still corrupted.

The geometry is pretty clean in itself so it's not just a sloppy model.
It's not real dense either, which sometimes causes display to look odd.

The model looks as it should when I render the viewport, it's just the editor view that's affected.

The display hardware doesn't have a problem anywhere else.
Video plays fine, images display right, no lag or fragmentation anywhere beside the viewport.

I'm hoping it's not actually a hardware problem.

Any ideas?

06-19-2008, 05:39 AM
Does this problem also occurs on another mesh, or just this one?

06-19-2008, 07:15 AM
It doesn't happen to other meshes.

It's now happened to all the inactive objects.
It wasn't like that before.

It's in the entire scene now.
I've never seen that happen before.

That irritates me!
SOB :scream: :argh: :banghead:
Fortunately I keep copies of most of the objects I model separately so I can use them again or modify them.
There were some models that I didn't save out though.
Like a large metal grate which was tedious to build.

I have no idea what could cause something like that to happen.

06-19-2008, 07:24 AM
Try creating a new camera and using that to view the scene, you could also try merging the document into a new empty document.

06-19-2008, 07:25 AM
Have you tried to copy and paste the scene into a new file?

06-19-2008, 07:40 AM
How about zipping up the scene file and uploading? I'm sure someone can pinpoint what the problem is. Looks like a heck of lot of polygons in there to me.


06-19-2008, 03:35 PM
Looks like a heck of lot of polygons in there to me.
I was thinking that myself.
I've worked with alot more polys than that before though.
I'll be annoyed if that's the result of too many polys, since it doesn't seem to be so many that it corrupts the display.

I'm trying to use standard box-poly modeling for archviz style scenes to have some work to show an architectural firm I do occasional work for that it's a viable method for creating semi-photorealistic arch-viz scenes that lean more toward aesthetic appeal than precision measurements.

It takes a healthy poly count to be able to add the small details.
Which of course can proliferate.

They usually have me do what amounts to matte paintings of a few renders out of Form-Z that I bring together to result in high rez image manipulations that they print out in large format on a plotter.
I add some basic 3D elements in cinema, light the scene and render in layers and comp them in PS.

Which none of their technicians can do themselves.
So my intention is to further assimilate myself into their workload using methods that their technicians can't reproduce so they give me more work.

Here's the zipped file-scene_file (http://home.comcast.net/~b.ballerin/filez/c4d/scenez/scene_file.1.c4d.zip)

I saved the building out alone, then opened it and it looked fine.
So I started deleting some polys along the edge of the trim that were made wrong because I couldn't see what I was doing with the mesh corruption.
As I was selecting them, the corruption came back.
It took a few minutes though.

I'm just gonna rebuild the whole scene using a different strategy.
Instead of making the whole mesh dense, I'm gonna add density to only the edges where it's needed.
I have a handicap where I have it stuck in my mind that the whole mesh has to be uniform quads.
It bothers me when the flow of the polys isn't uniform.
It's like a small obsessive-compulsive thing with me.

06-19-2008, 04:19 PM
I bet you were using the magnify tool. For some reason if you use this tool in the perspective viewport, the display becomes weird. What you need to do is to switch the camera for this viewport, and then go back to the original one. Should work.

06-19-2008, 04:41 PM
Reset the camera view by using the "Edit>Frame default" command.

P.S: This is an extremely dense mesh for the purpose.

06-19-2008, 04:48 PM
Changing the camera worked.

I don't use the magnify tool though.
I have a Shuttle device for editing video and I mapped the zoom in/out functions of cinema to the shuttles dials.
Aside from that I use the -&+ keys to zoom in and out which may be actually using the magnify tool.

Thanks for all the help.

If anyone has suggestions based on the scene file I posted, I'd love to hear em.

P.S: This is an extremely dense mesh for the purpose.
I knew it was, I just didn't know it was that dense.
The logic is that I don't like the results I get from hypernurbs on hard surface modeling.
Even when I weight the mesh, and/or use the linear R7 option.

How do you guys smooth hard surfaces while keeping the mesh at a workable density?
I know I have to get more familiar with weighting hypernurbs.
Any tips?
I hate real hard edged models with the "CG look", and using hypernurbs smoothes the mesh too much.

06-19-2008, 05:17 PM
Sounds like a job for beveled edges or perhaps the Chamfer plug by Remotion?

06-19-2008, 05:38 PM
After selecting 2 rows of polys the corruption came back after changing the camera.

Damn, how can this be?
It can't possibly be such a dense mesh that it just can't display.

06-19-2008, 05:45 PM
Try to export on OBJ of your mesh, reimport it and continue to work on that.
Your mesh might be corrupted somehow, and usually this fixes much things.
As for HN modeling, I wouldn't use it for archviz. Bevel your edges, as Wesware suggested.
The rest is part of classic modeling techniques.

06-19-2008, 07:13 PM
Try to export on OBJ of your mesh, reimport it and continue to work on that. I'll give that a try.
Exporting to OBJ tessellates the mesh doesn't it?
I can't stand triangular polys.
Too messy looking.

Bevel your edges, as Wesware suggested.
The rest is part of classic modeling techniques.
That's basically what I've been doing.

I guess the problem is that to create small details like trim design requires the mesh to be dense.
But the density that seems to be required such as in the building mesh I posted above is too dense.

To those of you who viewed the scene file I posted, do you see any problems with the scale of the scene?
I always use the mannequin primitive to judge scale.
Which is what I assume that primitive is for just like the real wooden dummies you use when learning to draw or sculpt, correct?

I'm just wondering because sometimes the dimension values of my objects seems excessive.
However, there's no basis of comparison that draws me to that conclusion, it's just a concern I sometimes have when I create a cube with a value of 8-10000 units on the X and/or Z axis.
But like I said, I use the dummy to judge scale, and I don't change the size of the dummy.
It doesn't seem like Maxon would create the dummy object with a bad scale that you're supposed to modify.
I could be wrong, but that does seem like a stupid thing to do on Maxons part to make the dummy object with a non-standard scale if that is the case.

06-19-2008, 07:27 PM
Without seeing the scene itself it's hard to say but it sounds and looks like you've either zoomed in or out the camera to the point where it's having difficulty overlaying the lines during the draw, it's purely a viewport drawing thing you mesh itself should not be corrupted, possible solutions include updating your graphics card drivers (or perhaps downgrading them), resetting your scene camera, scaling up/down your scene...

If you can share the scene then it would be much easier to diagnose and help you fix the problem (and avoid it in the future).

06-19-2008, 07:33 PM
Actually, the mannequin is 600m and Otto is at 366m .......
placing them directly into the scene.

Otto scales out at 6'-0" and mannequin is at 9-11"

These are C4D proportions when comparing the above figures.
The Zygote figures are normal scale as Otto and Meg.

I did a post on this back in April of 2007.

06-19-2008, 10:42 PM
Per A,
The scene file is in my 2nd post.

06-20-2008, 06:13 AM
I don't get those wrongly displayed polygons here when i open your scene. I can see some overlapping geometry in other parts, but it should not pose a shading problem.
I'm very sure it's your graphics card/driver acting up

06-21-2008, 05:38 AM
The overlapping of polys is most likely due to changes I made to the mesh when I couldn't see what I was doing with the corruption.
I was trying to create a lip on the outer perimeter of the recessed area by beveling, then smooth shift.
I couldn't tell what was happening to the mesh because the more I zoomed in the worse the fragmentation got.

That ended up killing the model because to fix that would require more work than just building the model all over again.
I would've had to delete the polys along the lip, then bridge all the edges.
Too tedious and a waste of time.

As to the idea of the problem being related to my graphics card drivers, I'm on a Mac with an Nvidia 6800GT and I don't think you can just update the drivers like you can on a PC.

I have a short time left on my Apple Care contract so I'll probably just call them and get a replacement card.

This problem isn't occuring now as I'm recreating the scene file and all models I lost.

I'm trying to keep the meshes as low density as possible.
Which seems like it'll be an annoyance since getting small details into a low density mesh isn't a natural act.

I'm gonna try right now, but would the copy/paste polys plugin work for this by creating 2 meshes one low density and 1 high density, then copying the finer details from the high poly mesh into only specific areas of the low density mesh?

Another strategy I've been pondering is to create the high density mesh and generate a normal map to apply to the low density mesh.
However, I've never generated a normal map like this, I've only used 3rd party utilities to convert a grayscale image(hand painted/optimized bump) into an RGB normal map.
Which doesn't really give me very solid results.
Same with the little NMG utility for the Mac, which is great in concept but the output leaves alot to be desired.

Crazy bump is the same way, great little app but it requires me to run it on an older PC.
And there's no way I'm gonna purchase it just to run it on an old PC.

What is the problem with Nvidia not offering a Mac version of their normal map utilities for photoshop CS3?
That's so annoying.

It should be theoretically possible to convert a bump to a normal map in photoshop by selecting certain levels of gray in the image and changing them to red-green or blue depending on the plane that each shade of gray represents.
I just don't know how to start to do something like that in photoshop.

Anyone else ever attempted that, or have any insight into how it could be done?

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