raytrace with dentil molding

[jpremodeler]

I have run into this problem in the past, but does anyone have a suggestion for raytacing with dentil? I have it on the exterior of a home, and all the ins and outs create ALOT of surfaces and it hangs up the raytracer.


Any insight would be appreciated. The plan is in the beginning stages, and needs a lot of work, but I figured I would ask.

Thanks!

[Alaskan Son]

Just a thought, but perhaps try to find or create and use a dentil texture instead and see how that looks.

[Dave Pitman]

When you get the exterior the way you want, you could convert the model to a symbol, which will take a little while, but when it is done, you can place the symbol in a new plan, and 'Trace away quite quickly.

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[amddrafting]

Or put the dentil moulding on a separate layer. Take a 3D shot of the house, turn off all layers except the dentil mould, then export to .3ds and then import as a symbol. Then just align it with the house.

[Alaskan Son]

Quick question. Why does changing to a symbol speed up the ray tracing??

[dshall]

Quick question. Why does changing to a symbol speed up the ray tracing??

That is a great question my friend. I would of thought there was just as many faces. I did try to do a raytrace of the project, and I think my 'puter ran out of memory. I could not get past the part where the program was processing for the raytrace. I did not try to turn it into a symbol.

[dshall]

Not that I questioned Dave or Aaron (well actually I did), but I tested it and they are correct. Turn the DENTIL FRIEZE (which is on the trim layer) to a symbol and it works much much faster. Thanks Dave and Aaron, I would of never guessed.

[Joe Carrick]

This is an interesting problem. That particular Dentil Molding has 16 surfaces and it's repeated several thousand times in this model. A Ray-
Trace has to evaluate every surface in the model for reflections, shadows, etc.

The number of surfaces doesn't effect the normal Render View with Pan and Zoom because of "Instancing" and how that's handled by the GPU. OTOH, Ray Traces are CPU bound and since each surface must be processed to determine it's effect on the Shadows and Reflections to other surfaces you get almost a geometric increase in the time the Ray Trace will take. The more cores, memory and cpu speed the better but it's still going to take a lot of time.

[dshall]

Yep, tested again with my own model, much quicker to turn the frieze into a symbol. Interesting.

[Joe Carrick]

Scott,

Once you created a symbol form the Frieze, how many surfaces were in that symbol? Maybe it's because the Dentil Molding has both inside and outside surfaces while the Frieze Symbol has only exterior surfaces and all the contiguous, co-planar surfaces become just one surface. ie: those surfaces are merged into single surfaces.

[dshall]

Scott,

Once you created a symbol form the Frieze, how many surfaces were in that symbol? Maybe it's because the Dentil Molding has both inside and outside surfaces while the Frieze Symbol has only exterior surfaces and all the contiguous, co-planar surfaces become just one surface. ie: those surfaces are merged into single surfaces.

The FRIEZE SYMBOL has 201847 faces................ ouch.............. I do not know how many the FRIEZE MOLDING had

[Joe Carrick]

The FRIEZE SYMBOL has 201847 faces................ ouch.............. I do not know how many the FRIEZE MOLDING had

Probably at least 600000 but maybe more. IAE, each surface has to be checked against every other surface in a Ray Trace.

200000 x 200000 = 40 billion checks
600000 x 600000 = 360 billion checks

But that doesn't account for all the other surfaces in the model nor for processing reflections off of other surfaces.