working with large, and small object scenes

[mhinks]

Hi all

 

Hope someone can offer some help for me. I've recently been working on some medical animations, not architectural I no, but this is such a good resource site, ill ask!

 

So these ani's, Im working with objects very small, ie 0.2microns, and less. But also had an environment that was a about 150mm square. I ended up working in mm, and had to scale everything up so I could keep the units above 1. The lighting for the scene was hell, I was using shadow maps of 5000+ and the computers half the time told the scee to sod off when rendering.

 

Im now starting a large scene where I already know Im going to have objects human size, and also low micron sizes. Help!! I want to get the scale of the scene right before modelling so Im not scalling things again. I ranin to a lot of problems with textures last time, having some preseduals at 0.001 size, and still being to big.

 

Lighting is the other problem, having such big shadow maps has a limit.

 

Hopefully some of you have had this problem with your work, and can help me out!

 

Thanks

[Jennifer]

Going from relatively large to relatively small can be problematic. The small scale objects can distort if there are roundoff errors introduced, and there are certainly practical limits depending on which System Unit Scale is used.

 

Have you tried raytraced shadows rather than shadow maps? At least that would conserve memory, albeit a potentially longer render. If you run out of RAM, then it would take forever with shadow maps anyway. How many lights are using shadows? Do all of them need to cast shadows? Defining 'includes' or 'excludes' for lights, and using light attenuation ranges can help a lot. Make only objects that need to cast shadows shadowcasting. Use spot or directional lights to confine the shadowcasting, if possible.

 

You may have to manually set or even animate the camera clipping planes, to go between large and small.

 

Perhaps consider making separate animations for the large-scale and small-scale scenes, and doing a transition between. Match the camera action as best you can, and use a dissove or blurry transition between.

 

Jenni

http://www.4dArtists.com

http://www.Render-Art.com

[mhinks]

Hi Jennifer

 

Thanks very much for your ideas. Im off sick, patched eye, so Ill spend some time going through them when I get back to the studio.

 

Hopefully these points will help others too

[William Alexander]

mhinks,

 

It might be possible to go the textures route on the micron sized objects at least in a macro view. Then edit / fade to a micron view using just the micron modeled portions.

 

rgrds

WDA