Re: Tagging DXF entiries/facets with refractive index [message #41230] |
Fri, 15 October 2004 11:40  |
nasalmon
Messages: 33 Registered: August 2003
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Rick Towler <rtowler@xxx.u.washington.edu> wrote in message news:<ckm93n$slg$1@gnus01.u.washington.edu>...
> Neil wrote:
>> Anyone have any ideas about how i might tag a DXF entity (or facet)
>> with a material property such as refractive index? I'd like to use one
>> of the software packages (OpenFX for example) to build up 3D scenes,
>> tagging each of the objects with refractive indices, then read the
>> complete scene in to IDL, using the DXF format and operate on the
>> individual objects in the scene.
>
> I am pretty sure you can't store refractive indices in .dxf files.
> If you can, it doesn't look like IDL can read them.
>
> Off the top of my head, you could use color or layers to encode your
> indices. Although color is an integer in the IDL_DXF_* structs it looks
> like the format is limited to byte values so you would be limited to 255
> levels (0 and 256 are reserved). With layers you could place objects
> with the same indices in the same layer and encode the index into the
> layer name.
>
> You should be able to do both in openFX.
>
>
>> I dont even know if i can tag objects with refrative index using
>> OpenFX, so would anyone know which 3D editor could do this?
>
> 3ds-max can. But again, If that data is exported in the .dxf file IDL
> can't read it.
>
> I am pretty sure that openFX doesn't export color data to .dxf properly.
>
>
>> Furthermore, i dont even know whether the DXF format can hold
>> refractive index, for each of the entities; it's not apparent from the
>> IDL Help that this can be done. If DXF cant hold this data, does
>> anyone know which common useable graphics format can hold this
>> information?
>
> And is easily readable by IDL? You may want to look into the old
> 3ds-max format ".max". It isn't readable by IDL but if it can store the
> refractive index (and you can afford 3ds-max to use as your authoring
> tool) then you can use code published on the web to dump the contents
> and go from there.
>
> If that isn't an option then I would either try encoding it in the color
> or layer name or create my own format where I import the geometry from
> .dxf and assign the refractive indices then.
>
>
> Good luck.
>
> -Rick
Many thanks for those tips, Neil
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