working with HUGE stp files

[judderman]

I have a project that I'm going to be working on soon, using stp files that have been modelled in something like solidworks or pro-e of a generator. I've used powersolids to import the stp files and that works fine.

My query is about working with these files and dealing with the difficult size of them. Has anyone dealt with stp files before and know how to optimise them? I have them at the coarse setting when imported, and they are still very detailed. I mean, this is literally every single component, nuts bolts, wiring and all in a huge generator that I have to be able to render and animate camera paths around it.

I was going to convert bits to mesh and then proxy them off - it's probably the only workable way I'd think? Maybe x-refs?

[instinct]

We tesselate in advance to taking it even to max these days. While "View dependent tesselation" and beeing able to tweak sound very fine in theory (and ARE in many cases) it is also a performance hog. Both max and esp VRay dont really have a problem with high polycounts. Tesselating prior to every frame IS an issue tho. So unless you need to fix the usual CAD Issues (Flipped surfaces, unstitched surfaces, missing trims or fucked up trims, missing fillets etc etc etc) I'd say tesselate and xref them.

Regards,
Thorsten

[andrewjohn81]

bolts and screws are actually Quite a bit of data. Those can Easily be instanced.

There's a tool on scriptspot that instances whatever you have selected when you run the script. I use it all the time. Just beware, only do it on things that have the same pivot. If it's actually the same object with the pivot in the center you'll have no problems.

I have had files go from about 400MB to about 60 or so in less than an hour of work. Well worth the time spent. They'll also render faster.

I also agree with Thorston. Once you've confirmed your surfaces are the same direction and checked your tessellation, convert to poly. And Xref that whole scene into your working file.

If much of it is hidden at a time you might also consider splitting the file into different sections if that is conducive to your workflow. For some renders you might just be able to turn one or two Xref's completely off.

A warning on Xrefs if you haven't used them in production where there may be thousands of parts. I'm not sure exactly where things go wrong, but they Can. I have had things suddenly jumble All around. I'm not sure if it's because of something where the names are the same as something else, or what...but just in case you might rename everything and just add a prefix/sufix to it with the numbered option checked or something. That's what I've been doing and haven't had a problem. Also, merge materials and controllers into the scene. That can screw up animation. Materials xreffed is Really messed up. It crashes a lot I've found. Some scripts will crash if they access an xreffed material. Not sure why. I'm a Huge fan of the rendermask script from this guy though: http://www.tepavicharov.com/

[kimgar]

good stuff andrew, i had forgotten about that instancer and the xref naming is a good pointer.
the jumping xrefs is still a mystery to me, it just seems random. has anyone tried the new container feature of max 2010?

regarding the million bolts, select by size and delete also does the trick

[andrewjohn81]

good to know we aren't the only ones who have jumping xref's.

And yes, delete is always one of the best cleanup tools.
It's a bit of a pain to do sometimes, but we have a lot of wire racks here. Usually they are joined together as a solid at spot welded points. Only...no one is going to notice if you unjoin each wire. When I do that, i can instance each wire and treat it as a separate object.

The pieces that kill me are large injection molded plastic pieces with Tons of holes in them. There's usually no good way of breaking that up in to more manageable pieces.

[judderman]

Thanks guys, these tips are great. I'm starting this now, will let you know how I get on.

[judderman]

Hi Guys,

Ran in to a problem already.



Don't know what settings I'm supposed to change. Why is v-ray rendering like this? Is the original stp file exported incorrectly?

[instinct]

An instant classic :P This is doublesided geometry. This should be fixed on importing by turning off a corresponding setting to be single sided. As a quickfix for finished conversion you could also SLIGHTLY up the secondary ray bias.

Regards,
Thorsten

[judderman]

Okay bizarrely, when I apply a vray material, it renders fine. Still, I'd like to know why it does that when it has no material on it. It sort of worries me when I come to rendering this beast :s

[judderman]

lol. Got it sorted. Cheers though!

[andrewjohn81]

yes, vray material Will fix that. OOoops, not if you turn on GI.

If you are using npower, they made a poor choice (in my opinion). They defaulted to 2 sided geometry for certain types. Make sure that gets unchecked, or you'll be regretting you didn't later on. Rendertime goes through the roof, even on a little baby part somewhere in your scene.

Happens all the time.