 | | | MObject from 'objectId ' ? | MObject from 'objectId ' ? 2003-11-26 - By Andrew Cammarano
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Given that solution, I guess I should mention the other possible
solution which would be to associate an identical copy of your shader
with each dag object (or group of components when relevant), and adding
a string attribute through which you pass the shape's dag path to your
shader. Triangulating to create a hierarchical database and then
searching it seems to consume processor cycles on a per sample basis
(and assumes that objectId's are static (which they most likely are))
while duplicate shader networks increases memory consumption. On the
other hand duplicating shader networks is a straightforward mel script,
triangulating, storing, and optimizing the database seems less
straightforward.
The Alias developer's I used to correspond with (when they were
Alias|Wavefront developer's) were aware of this issue. I can't remember
if the rationale for not adding hooks to the API was software related or
human resources/management related. In fact the shader per shape
workaround was suggested (reluctantly) by a rendering developer there.
Reluctantly, because he could think of no better solution giving the
problem.
-andrew
On Tue, 2003-11-25 at 16:15, Martin Leguizamon wrote:
> Rob,
>
> > Basically you have to triangulize your whole scene
> > and then store it into some format of your own, ordered
> > in primitive id order. There is some code from an
> > archive thread about this. Now when rendering you
> > can look up the primitive id in each of your shape
> > structures and can compare the vertex positions of
> > the triangle being rendered with the vertex positions
> > you have previously stored. Now if you have a match,
> > you can associate the object id with the shape.
> > Next time you get an object id which has already been
> > found you obiously don't need to go through the search
> > process again.
>
> Thanks for the tips. That is exactly what I implemented
> months ago in my shaders. See:
>
> http://products.provide3d.com/polyData
> http://products.provide3d.com/cpvData
>
> Seems that there is no other way to do it.
> Is any Alias developer reading this mailing ?
>
> Martin
>
> --
> Martin Leguizamon
> PROVIDE3D Developments
> http://www.provide3d.com - contact@(protected)
> +54 (341) 447-3389
>
>
>
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--
Andrew Cammarano
3D Department
LUMIQ STUDIOS
Lumiq SpA
Corso Lombardia 194
10149 Torino
tel.: +39 011 56.97.300
fax : +39 011 56.97.349
e-mail: andrew.cammarano@(protected)
web: www.lumiq.com
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