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 Problems with high poly counts
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dgdesign
Infrequent Poster

USA
29 Posts

Posted - 09/18/2008 :  09:47:02  Show Profile  Visit dgdesign's Homepage  Send dgdesign an AOL message
I recent bought Strata live 3D. I went through all of the tutorials and have learn a great deal about what this program can do. Yada Yada Yada... So far I haven't been impressed.

I have a timing belt and cog model that has been built with a tremendous amount of detail. Meaning has a high poly count, UV maps, etc... I exported the model as is to XMM and open it in Strata live 3D. My initial triangle count was 440,000 +. Of course this isn't going to work. It wouldn't load when I exported it to .JAR. I tried adjusting the count down (as noted in the online tutorials) to around 71,000 triangles. Below that, the model starts to look terrible. I also turned off "back face" in the materials to try and speed things up. Still didn't work. Wouldn't load. So, I went ahead a rebuilt the model just using simple extrusions and lathes from illustrator. The triangle count reduced to 200,000. Then to 50,000 after generating a new LOD and turning off back facing on the materials. Still nothing. The programs works as it's supposed to using a very low poly/triangulated model. I'm not having any luck with a higher poly/detail model. And to add another note... My UV map changes position when I bring it into Strata Live 3D.

I gave up on this program and tried to go back to animating a quicktime movie in Strata then converting it to QTVR using "QTVR Edit Object" (OS9 only). After hours of jacking around with this and rendering my movie, I finally realized that leopard and intel Macs no longer support OS9. (ARRRG!) So, I looked around on the internet for about 6 hours, downloaded every trial VR software that I could find and nothing works!

All I'm trying to do is have and interactive, online 360 rotation. Any suggestions?

I would be glad to send my model to someone who may be able to figure this out.

Brian Lawson
A Fountain of Information

USA
5217 Posts

Posted - 09/18/2008 :  10:04:48  Show Profile  Visit Brian Lawson's Homepage  Send Brian Lawson an AOL message
You can send your original Strata 3D CX model file to me and I'll be glad to take a look at it. Send it to support@strata.com.

Brian Lawson
Strata Technical Support
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jpro
A Fountain of Information

USA
4991 Posts

Posted - 09/18/2008 :  10:46:28  Show Profile  Visit jpro's Homepage
there are limits to what you can expect from high poly count models when you try to switch to realtime use. When we model something for realtime use, we generally _dramatically_ rethink how it will be modeled from the outset. Strata's extrude tool gives high poly counts by default, so I would not have used it at all. Thickness, on the other hand, gives low-poly results by default, provided you feed it a low edge-count profile.

as for QTVR, I'm pretty sure there are still viable options available. You might want to start another topic with that subject, maybe you can get some specific answers to your issues with QTVR.

Jean

Edited by - jpro on 09/18/2008 17:07:25
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jesmith
A Regular

USA
214 Posts

Posted - 09/18/2008 :  16:22:08  Show Profile  Visit jesmith's Homepage
Here are a couple rules of thumb:

- 30,000 triangles is an upper bound on what you should use on the web
- Automated decimation will NEVER look as good as what you can do by hand

This article has a link at the end you can use to get an idea of how polygon count impacts performance:

http://www.kaon.com/kb/article.php?id=008


-Joshua
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dgdesign
Infrequent Poster

USA
29 Posts

Posted - 09/19/2008 :  09:21:24  Show Profile  Visit dgdesign's Homepage  Send dgdesign an AOL message
Thanks for the feedback so far. I sent Brian my models. Hopefully he can shed some light on things. I will post another topic about QTVR in the Strata CX forum.
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jesmith
A Regular

USA
214 Posts

Posted - 09/19/2008 :  09:28:28  Show Profile  Visit jesmith's Homepage
FWIW, nobody uses QTVR for spinner-movies any more. You can easily do the same thing with Flash and not run into the "plug not available" problem.

Just google: flash vr

and a whole mess of competing tools come up.

-Joshua
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dgdesign
Infrequent Poster

USA
29 Posts

Posted - 09/19/2008 :  09:37:35  Show Profile  Visit dgdesign's Homepage  Send dgdesign an AOL message
jesmith -

Can you convert Quicktime movies to Flash VR?
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jesmith
A Regular

USA
214 Posts

Posted - 09/19/2008 :  09:44:17  Show Profile  Visit jesmith's Homepage
Beats me. I'm in the "Real 3D" business, so I don't actually USE any of those tools. I just know that whenever the boss asks me to look at someone else's fake 3d solution, they're using Flash, not QTVR. I literally have not seen a QTVR on the web in 7 YEARS! (Not that they do not exist, just that they exist on pages I have no reason to look at.)

The way QTVR works is pretty simple (it's a video with an algorithm used to jump around to different frames), so it wouldn't surprise me if one of those tools you can google has such a capability. On the other hand, since nobody uses QTVR, there probably are not a lot of market forces driving that import feature to exist. So maybe not.

-Joshua
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dgdesign
Infrequent Poster

USA
29 Posts

Posted - 09/19/2008 :  17:42:03  Show Profile  Visit dgdesign's Homepage  Send dgdesign an AOL message
I need to give a big THANKS to Brian. I sent him my model and he gave some really valuable feed back. I wasn't aware that when you extrude, lathe, etc... that by default the program will add a ton of extra, unnecessary polygons. There are several ways to go about correct this or avoiding this as you build your model.

JPRO suggested that I use "Thickness" on a poly mesh. I tried this and it worked for the most part. But it did add some stray lines that I couldn't seem to get rid of... It may work on less complicated or solid pieces. However, I got the same effect by just extruding my model that I imported from illustrator, converting it to a poly mesh. Going into edit mode, selecting my front face, then inverse selection, deleting everything but the front face and using the extrude tool under poly edit mode. There's more than one way to skin a cat.

So to sum it up... When I built my original model (direct import from Illustrator, then extruded) The poly count was 440,000 + Yikes!

Now my total poly count is 22,787. What a significant improvement! If I mess around with it more, I'm sure I can get it lower.

I haven't exported to Strata Live yet. When I do I will give another update.

Thanks again!
- Darren
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Brian Lawson
A Fountain of Information

USA
5217 Posts

Posted - 09/19/2008 :  17:48:25  Show Profile  Visit Brian Lawson's Homepage  Send Brian Lawson an AOL message
Those stray lines may have come from the Compound Path you created in your Illustrator document. When Strata imports a compound path it will connect the inner and outer paths to tie the two together. When you then extrude that Bezier Region that connecting line results in a polygon cutting across your mesh and you can not get rid of it without destroying your mesh in the process.

Brian Lawson
Strata Technical Support
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dgdesign
Infrequent Poster

USA
29 Posts

Posted - 09/22/2008 :  09:41:06  Show Profile  Visit dgdesign's Homepage  Send dgdesign an AOL message
One other issue that I'm still having is my UV maps are shifting position when I open them into Strata Live. How can I correct this?
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dgdesign
Infrequent Poster

USA
29 Posts

Posted - 09/22/2008 :  11:05:02  Show Profile  Visit dgdesign's Homepage  Send dgdesign an AOL message
OK... I've gone through rebuilt my model and made it as efficient as I can. My Polygon count is 15,000. When I export to XMM and open in Strata Live, my triangle count is 150,000. I've tried to adjust the count down and generate a new LOD. No Luck! I start losing detail around the 80,000 mark. The model becomes very choppy and it still won't load. I even tried to take my total count down regardless of what it looks like to under 30,000 and it still won't work.

At this point, I don't know if this is even possible with Strata Live. I know it's possible with other programs such as Zbrush. They have a turntable gallery with very detailed images on their site.

I'm at a loss... Any suggestions?

Edited by - dgdesign on 09/22/2008 13:25:46
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jpro
A Fountain of Information

USA
4991 Posts

Posted - 09/22/2008 :  11:58:03  Show Profile  Visit jpro's Homepage
the suggestions I have made are THE way to do it... the question now is how complex is the actual model you are working with, and how well did you optimize your geometry before using thickness. And yes, you definitely need to stick with thickness, not extrusion, but you have to do just a tad of problem solving along the way. I write up little demos for that every little bit here.

I don't know how your polygon count could possibly balloon from 15,000 to 150,000. Something went wrong. A quad count of 15,000 will become a triangle count of 30,000, but you must be doing something else that needs adjusted.

Can you send me your model? Don't send just your too-complex version, send the paths that you are going to extrude as well.

jpro2 [at] swbell [dot] net


Jean
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jpro
A Fountain of Information

USA
4991 Posts

Posted - 09/22/2008 :  14:21:36  Show Profile  Visit jpro's Homepage
Okay, Darren. Earlier, I said we need to dramatically think our modeling approach for realtime, and that you need to use low-edge count profiles for thickness. This is what I mean



In illustrator, I would draw with straight-segment lines only, no curves. This allows you to control how many edges/polygons Strata creates when the modeling process proceeds. I took a small portion of one of your cogged wheels and hit each point with the convert to corner point tool.

If this were my project, I would have drawn all the teeth like that to begin with. If I had to convert a drawing at this point, I would buy one of the Illustrator plugins that would automate this task for me. Feeding Strata curves means Strata will generate a lot of polygons to describe those curves: way more than you need for real-time viewing.

For larger curves, say a big cylinder, I would start with a polygon instead of with a circle. A 30- or 32-sided polygon will look smooth when it is rendered with smoothing in a realtime setting. You could test a few variations and see what might work, but you probably won't want to go lower than 24 sides on a large piece.

It all depends upon how you do your modeling as to how many polygons Strata will by default use when converting the object to polygon mesh. But the single most important thing you can do is draw your profiles with straight lines, not curves, and don't use any more edges than is absolutely necessary.

Jean
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jpro
A Fountain of Information

USA
4991 Posts

Posted - 09/22/2008 :  14:42:14  Show Profile  Visit jpro's Homepage
Here are some additional tips: be aware that strata is giving you a polygon count that includes ngons and quads, where live 3d is going to be dealing with triangles. Each quad will become 2 triangles, so expect the polygon count of a quad model to double. If you have ngons, they will be divided into triangles, too. A 24-sided ngon will be divided into 22 triangles for Live 3D use.

To get a better idea of how many triangles will be generated upon export, apply 0 level triangle subdivision to all your meshes. Now the polygon count Strata will give you for your model with be a triangle count, not a literal polygon count.

This will still only be an approximation, but you can get a much more realistic estimate of your final triangle count tis way. This is a live preview of the triangulation that will happen upon export.

as we have alredy discussed, avoid extrusions when you want low poly counts.

If you feed the lathe tool low edge count profiles, it can be used to do nice low-poly models. You do this by selecting linear segments,setting an appropriate number of segments, and setting complexity to 0 before converting to polygon mesh.

Path extrusions can be controlled similarly.

To avoid the unwanted connecting faces you are getting, all you need to do is never feed Strata a compound path when you want to convert to polygon mesh. You alwasy want to model the hole explicitly in Strata, in the polygon modeler. The easiest way to do this is to leave a gap in your path in Illustrator, and bridge in the polygon modeler to finish describing the hole.

Jean

Edited by - jpro on 09/22/2008 15:19:56
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jpro
A Fountain of Information

USA
4991 Posts

Posted - 09/22/2008 :  14:56:35  Show Profile  Visit jpro's Homepage
No compound paths:

Here's how we do that. Instead of feeding Strata a compound path, feed it paths that describe part of the object, then model the rest in Strata.

One way to model a cylindrical object with a hole in the center: give strata the green paths, then convert to polygon mesh, then bridge the red faces in. (This isn't the best way to do a cylinder with a hole, I am just using a cylinder as an example here. note I used polygons in illustrator, not circles, so I can control my edge count) Then use thickness.





Jean
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