Memory vs Processor

[Kromar]

it might be helpfull to know what your current system is to give you some upgrade advise :deal:
and maybe some details on this CAD model, maybe the problem is not your hardware.

[pxlgraf]

intel Core 2 Duo CPU E6750 @ 2.66GHz

8 MB RAM

Linux CentOS 5, kernel 2.6.18-92.el5, x86_64,

I can't give out much info about the CAD model for legal reasons but it is a mechanical assembly. I've gone over it for 'problem' geometry and haven't found anything yet.

[Kromar]

hmm do you use a complex shader on the CAD model? i dont think your hardware is the problem there.

[Bullit]

Probably a Geometry problem, duplicate faces, scale etc... If you can remake the model in Blender it is probable the problem disapeers.

[Apollux]

intel Core 2 Duo CPU E6750 @ 2.66GHz

8 MB RAM

Linux CentOS 5, kernel 2.6.18-92.el5, x86_64,

I can't give out much info about the CAD model for legal reasons but it is a mechanical assembly. I've gone over it for 'problem' geometry and haven't found anything yet.

I hope you mean 8 GB and not 8 MB.. if it is the latter, then you NEED more ram :eek: (Just kidding).

How many verts/polys are in the scene before and after you add the CAD model ?.. that's the first thing to look at.

[pxlgraf]

yes, it is 8GB of RAM.

there are no complex shaders on the CAD model.

I'm less concerned with tweaking this scene than I am in getting a better understanding about how Blender works. In this case, during a render, both CPU's are working at 100% or close to it, but only 2 to 3 GB of the 8GB are being accessed. Does Blender not need to use this RAM or is something not letting it access it? If these CPU's are upgraded to faster processor's will I see a real improvement?

Would an optimized build be a way of accessing more of this RAM?

so many questions....

[Yecire]

I noticed that your OS is 64bit ... are you using a 64bit build of Blender? If you are, it may just be that the scene doesn't require more RAM. As for rendering speed, it's all on your CPU ... RAM will only determine how complex of a scene can be handled, not how fast it renders.

[pxlgraf]

yes, I'm using the 64 bit build. It looks like I need to simplify my geometry or get more computing power. Thanks for everyone's help.

[Michael-Williamson]

Does the cad model increase the "area" of the scene considerably?

I've noticed myself that when raytracing or using ambient occlusion that even very low poly geometry that considerably increases the footprint of the scene can suddenly make the render time go from under a minute (on the scene in question) to over half an hour per frame.... or worse...


Unfortunately I don't have an answer, other than rendering in passes and compositing to try and get the speed up... that way you can only raytrace the stuff that needs it for example...

If it's the AO that's the problem there's lots of values to tweak that can bring the render speed back down and still keep acceptable quality on a larger scale model....

[harkyman]

Do the windows in your cad model use raytraced transparency? If so, that's probably the issue right there. Try adjusting the materials for glass to use zTransp instead of RayTransp.

[TheNeverman]

what's going on in your shader setup? any reflections or transparent pieces? procedural or texture mapped materials?

[Apollux]

Does the cad model increase the "area" of the scene considerably?

I've noticed myself that when raytracing or using ambient occlusion that even very low poly geometry that considerably increases the footprint of the scene can suddenly make the render time go from under a minute (on the scene in question) to over half an hour per frame.... or worse...


Unfortunately I don't have an answer, other than rendering in passes and compositing to try and get the speed up... that way you can only raytrace the stuff that needs it for example...

If it's the AO that's the problem there's lots of values to tweak that can bring the render speed back down and still keep acceptable quality on a larger scale model....

When that happens, the Octree Resolution (Render settings) is the most likely culprit.

[Michael-Williamson]

When that happens, the Octree Resolution (Render settings) is the most likely culprit.

I figured as much (mostly I do realtime stuff)
I found that setting in the buttons once and have been un-able to find it again! I'll look it up in the wiki!


thanks for the tip!

[durbdk]

I work on mechanical systems using AutoCAD, and I often export assemblies to Blender in order to make beauty renders/walkthroughs and product galleries. When I import a system...say a simple conveyor...then I ende up having about 5 to 10 times the geometry I really need. Designing in CAD is a meticulous job; when first starting out with using Blender at work, I discovered that just by removing the washers from the CAD model, I saved over 100,000 polys, geometry is what kills you in the process. Look at your model and identify how many hidden or internal faces you have in it, then remove them. This simple process will result in a faster viewport, render and a smaller file size. There is plenty of optimization to be done in the render phase, but starting out with such a large file (which most CAD files tend to be) does nothing but hurt the process.

Reduce the geometry, then look to shaving time on the render.

Good luck!

[CGTalk Moderation]

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.