Howdy folks.
Been playing with the new "drape" command in AutoCAD 2006. This command makes it extremely easy to create terrain meshes, and I'm working on a project that is located in a valley so I thought it'd be nice to be able to model the valley since the mountains provide some considerable shading in the morning and afternoons. But of course now my octree bounding box is quite large, which leads me to this ditty from the rtrace manpage, regarding the -ar parameter:
*"*The maximum ambient value density is the scene size times the ambient accuracy (see the /-aa/ option below) divided by the ambient resolution."
By having such an expansive outdoor geometry, am I forcing a very high -ar in order to get good data from rtraces in an interior space, or if I use enough -ab will this not matter? A test render looked very flat too; I thought it was the mellow settings I used for the test render, but now I'm concerned that without -ar's in the thousands (!), my renderings will always look very flat.
- Rob Guglielmetti
www.rumblestrip.org
If your outdoor scene is hundreds of times larger than your indoor scene, you are probably better off setting -ar 0 and just suffering the long render times in the inside corners. If the bounding cube is less than a hundred times larger than your interior space, then just increase your -ar setting by the corresponding factor, or let rad figure it out for you.
-Greg
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From: Rob Guglielmetti <[email protected]>
Date: November 18, 2005 3:19:58 PM PST
Howdy folks.
Been playing with the new "drape" command in AutoCAD 2006. This command makes it extremely easy to create terrain meshes, and I'm working on a project that is located in a valley so I thought it'd be nice to be able to model the valley since the mountains provide some considerable shading in the morning and afternoons. But of course now my octree bounding box is quite large, which leads me to this ditty from the rtrace manpage, regarding the -ar parameter:
*"*The maximum ambient value density is the scene size times the ambient accuracy (see the /-aa/ option below) divided by the ambient resolution."
By having such an expansive outdoor geometry, am I forcing a very high -ar in order to get good data from rtraces in an interior space, or if I use enough -ab will this not matter? A test render looked very flat too; I thought it was the mellow settings I used for the test render, but now I'm concerned that without -ar's in the thousands (!), my renderings will always look very flat.
- Rob Guglielmetti
Greg Ward wrote:
If your outdoor scene is hundreds of times larger than your indoor scene, you are probably better off setting -ar 0 and just suffering the long render times in the inside corners. If the bounding cube is less than a hundred times larger than your interior space, then just increase your -ar setting by the corresponding factor, or let rad figure it out for you.
Setting -ar 0 switches off all interpolation, I guess? Thanks Greg. I'll look at that, or maybe just use the mountain geometry with -ab 0 and use that model to see how much the shading is working for us.
- Rob
Hi Rob,
Actually, -ar 0 just turns off the limit to value spacing, so you'll basically get one interreflection calculation per pixel on inside corners. Interpolation still takes place when surfaces are farther apart. To turn off interpolation altogether, you'd have to set -aa 0, which is another (somewhat more drastic) approach to the scaling problem.
-Greg
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From: Rob Guglielmetti <[email protected]>
Date: November 18, 2005 3:58:23 PM PST
Setting -ar 0 switches off all interpolation, I guess? Thanks Greg. I'll look at that, or maybe just use the mountain geometry with -ab 0 and use that model to see how much the shading is working for us.
- Rob