Cam select modifier ?

[tom schuelke]

Well i post this for Jonnybefree here.

Our problem a very big Scene with lot of trees.

Jonas idea now is not only to use vray proxies, which allready works...

but to use a tool we both have seen somewhere.... sometime... dont know anymore...

to render a big Scene the guy that time deleted automated everything that wasnt in the area of the cam, while rendering...

do you know anything about this, or doesnt this make no sense anymore with vray and vrayproxies.. Our problem rather is the rendertime.

Here a screenshot for you to get an idea what we want to achieve... but automated, and then delete everything invisible to the cam.




Tom

[joconnell]

Yup - it's done by making a cone object in the shape of the camera field of view and parenting that to the camera. Next you apply a volume select modifier to everything in the scene, choose mesh object as the volume type and pick your camera cone. You set the volume select to invert so that only polygons outside the camera cone get selected and then feed that into a delete mesh modifier.

You run into 2 problems with this - First of all you already have the geometry in the scene so it's taking the same amount of memory to load it but now you also have the volume and delete mesh modifiers too - extra memory overhead.

Second of all because you are using a delete mesh it means you need to have a really high density mesh to have accurate control over the polygons that get selected and deleted so you need to tesellate things more than normal.

Third of all since you're using GI and probably raytracing, things outside of the camera will still have an effect on the scene either by appearing in the reflections of windows or by adding / removing light with the GI solution. You'll end up with shadows popping on and off, objects appearing and disappearing in reflections and pops in your GI solution as objects that previously either bounced light around or sucked light out of the scene suddenly disappear.

What you're describing here is really something like the reyes approach that renderman uses and that only works with scanline rendering - as soon as raytracing or any other light bouncing techniques enter the equation it falls apart because of the same issues.

Unfortunately there's no way around it aside from using lower res trees or breaking your render into passes.

[studioDIM]

One suggestion about trees in forest numbers: Unless you have them very close to the camera, avoid opacity mapping entirely.
I sent Johnny a picture from an 1850 trees, 18 types park.
None of those have leaves other than rectangles.
For the close-ups, a bit of Video Editing and some material change to enable the opacity mapped leaves did the trick.
If only MSN worked, ffs...

Lele

[dbuchhofer]

looks like blurs blinders script is probably the one you saw before. haven't used it however

[tom schuelke]

Ah Well,

thank you for your comments...

Yes i also thought about a mesh selection modifier, but i thought there maybe would be something more automated inside max, i didnt remember anymore.

and yes i also didnt beleave, this could speed things up.

so i think , vlado´s vraymesh and using only polygoons for trees is right now the best option one can have.

thanks.


Tom

[joconnell]

looks like blurs blinders script is probably the one you saw before. haven't used it however

Even blur have said they've dropped using it - for whatever speed up you may get you lose man hours going back and fixing all of the errors caused by it.