Transparent Textures in Radiance

Hi All,

Is it possible to have transparent textures in the mesh primitive? I
have a student who wants to map a logo around a beer glass and I can't
find a way to do so but hope to be proved wrong!

Thanks

Rich

···

____________________________

Richard Gillibrand

Department of Computer Science,

University of Bristol,

Tel: 0117 9545256

____________________________

R Gillibrand wrote:

Hi All,

Is it possible to have transparent textures in the mesh primitive? I have a student who wants to map a logo around a beer glass and I can�t find a way to do so but hope to be proved wrong!

you may find

    void plastic mp1
    0
    5 .01 0.01 0.01 0.35 0.1

    void glass mp2
    0
    ...

    void mixpict mp
    15 mp1 mp2 digital1 sp.pic picture_UV.cal tpic_u tpic_v ...
    0

useful. (or substitute trans for plastic to get translucent writing)

-Peter

···

--
pab-opto, Freiburg, Germany, www.pab-opto.de

Hi,

this thread is rather old, however I just came to the same point. No, not to a glass of beer, but to the adventure of using a new modifier type:

(12/02/03) Peter Apian-Bennewitz wrote:

R Gillibrand wrote:

Hi All,

Is it possible to have transparent textures in the mesh primitive? I have a student who wants to map a logo around a beer glass and I can’t find a way to do so but hope to be proved wrong!

[...]

   void mixpict mp
   15 mp1 mp2 digital1 sp.pic picture_UV.cal tpic_u tpic_v ...
   0

I understand mp1 and mp2 (the modifiers to mix), digital1 means there is 1/0 substitution, where is it defined, or do I have to define this function? Than sp.pic as the picture, ok, with white meaning foreground mod, black background? Finally picture_UV.cal, I guess you wanted to show the need of a beer glass mapping func ;-)?

All I know about mixpict is from ray.pdf, is there any other source?

I have some kind of mosaic that I don't want to model geometrically. It consists of three different materials. I have material definitions (plastic) of all three. Can I use mixpict to create some kind of "mask" in radiance? Is it possible to use a mixpict modifier as a background in mixpict (I think I would have to do so if I want to combine three, not two)? Finally - is it more adviseable to assemble the mosaic in a bitmap editor (gimp, photoshop & co) and apply it by using the colorpict modifier?

TIA+CU Lars.

···

--
Lars O. Grobe
[email protected]

Hi Lars,

Using mixpict to achieve transparency can be done in one of two ways. The preferred method is to specify "void" as one of the alternate materials, either foreground or background, and where the mixpict evaluates to 1 (or 0), the surface will be disregarded. The other alternative is to specify a trans material with the following parameters:

void trans passthru
0
7 0 0 0 0 0 1 1

If I remember right, this will send the ray straight through without any alterations, though it is slightly more expensive than using the "void" modifier. For more information, check out this entry in the old Radiance digests:

  http://radsite.lbl.gov/radiance/digests_html/v3n0.html#OPACITY_MAPPING

-Greg

···

From: "Lars O. Grobe" <[email protected]>
Date: July 19, 2004 12:02:35 PM PDT

Hi,

this thread is rather old, however I just came to the same point. No, not to a glass of beer, but to the adventure of using a new modifier type:

(12/02/03) Peter Apian-Bennewitz wrote:

R Gillibrand wrote:

Hi All,

Is it possible to have transparent textures in the mesh primitive? I have a student who wants to map a logo around a beer glass and I can’t find a way to do so but hope to be proved wrong!

[...]

   void mixpict mp
   15 mp1 mp2 digital1 sp.pic picture_UV.cal tpic_u tpic_v ...
   0

I understand mp1 and mp2 (the modifiers to mix), digital1 means there is 1/0 substitution, where is it defined, or do I have to define this function? Than sp.pic as the picture, ok, with white meaning foreground mod, black background? Finally picture_UV.cal, I guess you wanted to show the need of a beer glass mapping func ;-)?

All I know about mixpict is from ray.pdf, is there any other source?

I have some kind of mosaic that I don't want to model geometrically. It consists of three different materials. I have material definitions (plastic) of all three. Can I use mixpict to create some kind of "mask" in radiance? Is it possible to use a mixpict modifier as a background in mixpict (I think I would have to do so if I want to combine three, not two)? Finally - is it more adviseable to assemble the mosaic in a bitmap editor (gimp, photoshop & co) and apply it by using the colorpict modifier?