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View Full Version : Serious need for poly-crunching!



ray_tracer
10-25-2005, 10:50 AM
I've been given a CAD model to animate but it's obscenely polygon-heavy so I'm working my way through the various layers trying to reduce the thing. One layer, particular, has a lot of pipes and a total of some 300,000 polys. Each pipe has 416 SIDES!!

The poly reduction tools frequently leave holes in the mesh that have to be repaired one by one so I thought I might use one of the orthogonal views in wireframe to select every third or fourth vertex and delete 'em. Unfortunately, the pipes are almost exclusively at angles that won't allow this.

I don't get nearly enough practice in Lightwave to know all of the tricks and so far I haven't had any luck finding a relevant entry in the help guides. Can anyone put me onto a good way to reduce the numbers of side on these things?

Thanks!

jpaugh78
10-25-2005, 11:08 AM
would the "remove points" plugin work maybe? you can find it in the following post:
http://vbulletin.newtek.com/showthread.php?p=299999#post299999

GregMalick
10-25-2005, 11:25 AM
Man! I'd rather just model the pipes by hand than have to remove points one at a time. There are some plugins specificatlly designed to help with making pipes - although just plain extruding them is pretty easy. I'm not familiar with that mentioed plugin - maybe it's great.

I don't envy you. I'll be watching this thread for other ideas.

Could you post a pictures of the myriad of pipes. It might help by seeing what you are up against.

Oh BTW - depending on the animation - you might be able to use compositing to your advantage. All the static BG stuff could be rendered and the front animated parts composited in. All it will help with is the animation render time. But this all depends on what your camera has to do.

GregMalick
10-25-2005, 04:38 PM
This just showed up today in the forum.

http://www.mootools.com/plugins/us/polygoncruncher/index.asp

I don't know how good it is - you might want to check out the 7-day trial. Hopefully your gig is paying enough to cover the cost. :D

Matt
10-26-2005, 08:00 AM
I use reduce 'Reduce Polys' a lot, works well on geometric models, no so good for organic. That's when I just use the existing points to create curves for spline patching, it doesn't matter how messy the underlying curves are (from the gazzilion points on the original model) because when you patch you specify the number of points on the patch mesh, also whether they are uniformly spaced etc.

I used to think spline patches used the points on the curve, so I never thought to use them for cleaning models, they're actually very, very useful!

liquidpope
10-26-2005, 11:32 AM
Do you still have the CAD files? Are you exporting them from CAD to LW?
You could re-export them with a lower "rendered object smoothing" setting to reduce the number of sides per pipe. That would be the quickest, easiest way to reduce polys.

DonAVP
10-26-2005, 12:12 PM
This is a subject near and dear to my heart. I get to do this about twice a year. Usually need to hire others to help.

If you have PolyTrans it has a poly reduction program within it. It does a fare job and you can control how much it reduces. Within LW is a plug-in call qemLOSS3 http://amber.rc.arizona.edu/lw/qemloss3.html. This works well also and can work with UV maps. The main trouble with these programs is that the reduction is usually so great that like you said holes, tars and distortion occur.

There are two areas that you can work this. First contact the person (if you can) that created the CAD file or if they convert it see if they can do a little work on their end to make it cleaner. You did not mention which CAD program they have. I believe (wishful thinking) some CAD programs can help in reducing data (polys) before export. The second is use the programs mentioned above but only reduce to a point that leaves the look good. You will need to go in and mess with the model by hand eventually. Like has been said, sometime you can model faster that mess with what you have. LW is very, very fast and with a little practice quicker creating that cleaning.

To get to weird angles or planes on a model I use and swear by cplane http://www.ats-3d.com/cplane/cplane.htm. I don't how I could have done some of the cleaning/remodeling without this plug-in. One caveat, once you have run the plug-in. If you have any layers turned off or polys hidden don't turn them back on and flip the model back to normal orientation. You will have lost the orientation of what had been hide or off. Save the object just before you use cplane the first couple of times so you can get back to something good. As far as I know the mult-undo's do not work nice with cplane up to the point that you flipped the model.

Hope this helps and I would like to hear of any other way folks are dealing with this subject both free and commercial. I will check out the earlier post by GregMalick

Don

Castius
10-26-2005, 12:21 PM
Are you using qemloss3? If your not, I'd suggest you try it. I've never know it to leave holes.

lardbros
10-28-2005, 04:41 PM
BandGlue could help with some of the pipes! Just select a few polys in a few rows that you would like to merge and then click bandglue! As long as the polys are following the same flow, it will remove as many as you select! Certainly quicker than merging or deleting and building over again.

habaņero
10-28-2005, 07:33 PM
Say you want 8 sides to those pipes. Use the new select loop, use the new select nth and pick "52". Save this as surfaces. Select loop again and deselect the surface with w. save as a surface. Now you can use bandglue, add the last rows in the end or underways.

Point sets are an alternative as well.