techniques for retopologizing a car

Become a member of the CGSociety

Connect, Share, and Learn with our Large Growing CG Art Community. It's Free!

THREAD CLOSED
 
Thread Tools Search this Thread Display Modes
Old 04 April 2013   #1
techniques for retopologizing a car

we are having to rendering out a movie with car cad data in the amount of 20million or so in geometry poly count. this creates gives us long render times in vray. about 5 hours a frame or so with motion blur at 1920x1080 with moderate subdivisions and noise samples. Vray Proxying the geometry only makes the render go slower. So i am looking into ways to reduce the amount of geometry in the scene. Anyone has suggestions on how reduce geometry count on a cars?
__________________
CALIBER STUDIO
 
Old 04 April 2013   #2
I guess it depends on how detailed it is, if you need the detail then it's possible you won't be able to reduce the poly count without going below acceptable levels. An ideal situation would have the parts modeled optimally, to where it's not wasting geometry.
__________________
The Z-Axis
 
Old 04 April 2013   #3
Originally Posted by cooperunionstud: Vray Proxying the geometry only makes the render go slower.


This shouldn't be the case at all. Odd...

If you have access to Zbrush you could try importing the 20mio mesh(could be problematic) and use Qremesher to reduce the polycount and reproject the high res details. The topology won't be ideal but then again your cad data probably isn't either...

Last edited by musashidan : 04 April 2013 at 10:04 AM.
 
Old 04 April 2013   #4
V-ray is exceptionally good at handling high poly counts so I'd imagine that it's the size of the file that's causing a bottleneck. Are you rendering it across a network? If so, using a proxy and storing a local copy of the .vrmesh file on each node should speed things up considerably.

If that still doesn't work then I would also recommend taking it into Zbrush, but I would use decimation master rather than Qremesher as it would struggle to retain the detail from something like a car. The only other option would be to manually re-topologise it using the Graphite tools and PolyDraw but it will take some time.
__________________
SKETCHBOOK
MDI
moonjam.com
 
Old 04 April 2013   #5
Why not just import the model into Max in sections if need be, and use the retop tools in Max ?
That with the Wrapit plugin should be a cinch to lower the resolution - bit of turbosmooth on top.

http://matt-clark.co.uk/wrapit/

This may help as well :
http://mariussilaghi.com/products/turbosmooth-pro
__________________
Renderfarm hire available @ www.hotknife.co.uk
 
Old 04 April 2013   #6
Originally Posted by AJ:
If that still doesn't work then I would also recommend taking it into Zbrush, but I would use decimation master rather than Qremesher as it would struggle to retain the detail from something like a car.
.


I also thought of this but the triangulated faceting caused by decimation master might cause horrible render artifacts with something like a car surface. Also, with the Qremesher guides you could control the contours of the car reasonably well.
 
Old 04 April 2013   #7
Qremesher has limitations when it comes to detail sadly so you would have to manually add all of the fillets and edges to each panel.

I've used Decimation Master to thin out some dense nurbs geometry before and it's done a fantastic job. That said, those objects were very curved so I can see your point that flat surfaces might become horribly triangulated.
__________________
SKETCHBOOK
MDI
moonjam.com
 
Old 04 April 2013   #8
Originally Posted by AJ: Qremesher has limitations when it comes to detail sadly so you would have to manually add all of the fillets and edges to each panel.



Agreed. Whilst Zbrush has come on immensely as a hard-surface modeller in recent releases, the bridge between multi-million hard-surface meshes and production assets still has to be crossed by manual retopology for the most part.
 
Old 04 April 2013   #9
Quote: So i am looking into ways to reduce the amount of geometry in the scene. Anyone has suggestions on how reduce geometry count on a cars?


Without seeing the car, or the mesh, no. Without knowing the file-type of the car-data, no. Without seeing the scene no. Can you show these things or are is there a non-disclosure agreement?

Is the interior and engine fully modelled as well? because I have modelled my own car including an AMG V8 Engine (not yet finished) and with everything smoothed its only about 8 million polys.
 
Old 04 April 2013   #10
Inside 3ds max I would:
1) Use ProOptimizer to optimize the mesh as it is designed to deal with Triangles and is designed to (when enabled) do it's best to Preserve Vertex Normals. You can also enable merge vertices (0.0) to fuse surface edges together.
2) Look at your vray render settings. Is your noise threshold really at a value it needs to be at for the shot? What about Geometry Type? What are the sample settings for motion blurred objects? What are the sample settings for the non-motion blurred objects?

-Eric
__________________
"The Evil Monkey hiding in your closet."
 
Old 04 April 2013   #11
Also, to add to your research, the auto and curve based topology tools in the Mudbox 2014 are quite sophisticated in preserving detail and creating quads from massive triangular datasets. The research part is, I've never tried it with a 20 mil mesh, also of course, it's not actually out yet.
__________________
________________________________________
MEC 2014
 
Old 04 April 2013   #12
Thread automatically closed

This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.
__________________
CGTalk Policy/Legalities
Note that as CGTalk Members, you agree to the terms and conditions of using this website.
 
Thread Closed share thread



Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
CGSociety
Society of Digital Artists
www.cgsociety.org

Powered by vBulletin
Copyright 2000 - 2006,
Jelsoft Enterprises Ltd.
Minimize Ads
Forum Jump
Miscellaneous

All times are GMT. The time now is 07:14 PM.


Powered by vBulletin
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.