CREATE A PNG WITH TRANSPARENCY IN PHOTOSHOP
First, open the texture you want to modify in photoshop. Create transparent voids using whatever method you like to select and delete portions of the texture (One method is to use the Magic Wand with “Contiguous” un-checked to select. Another method is to use the Select > Color Range tool). Make sure that when you delete these areas, you see the white and gray checkered background that denotes transparency in Photoshop. Flatten and save the file as a .png.
APPLY THE SURFACE IMAGE TO THE SURFACE SETTINGS
Using the Library Manager, upload the surface to a surface or textures folder in the Embedded Library. Then, in the Surface Settings dialog, create or duplicate a surface while in the Internal Engine settings and add the image using the search command in the Texture section.
There are only two steps for the “screen” effect:
1. Check “Transparency” in the alpha channel effects area. This determines whether the voids you created in your .png display as opaque white spots or truly transparent voids.
2. Decide whether to use the “Transmittance” parameter. This parameter has two effects. The first effect determines whether or not the surface casts a shadow. At 0, the surface casts shadows like a normal opaque surface. You might want to stick with 0 if you have a very dense material, like a dense rain screen that will cast a heavy shadow in real life. The second effect is the degree of transparency of the material. At a value of 1, the surface stops casting shadows entirely, but the solid portions of the texture are still completely opaque. This is useful for lighter meshes or screens that will only cast a faint shadow. (Unfortunately, there are no degrees of shade in Archicad’s internal engine – shadows are only either on or off.) At higher values of transmittance, the surface becomes increasingly more transparent, which can be used to tune how well you can see beyond the surface and correct for a texture that is too dense/dark. At 100, the surface is completely invisible (and mostly useless).
MATCH THE SETTINGS FROM INTERNAL TO CINERENDER
Once the on screen view (internal engine) is set to the correct scale, transparency, reflection, etc., switch to the CineRender surface settings and match CineRender from Internal Engine. A quick, low resolution test will show wether the match is correct for rendering. I recommend rendering these tests at 150 dpi or less using the “Outdoor Daylight Fast” preset; this will give you a reasonable quality view in less than 60 seconds.
– PV / PJM