transparency in image prop

[Ziska]

I posted this over in the general discussion- but Nicholas suggested I try posting here- so ....

Illustrator file from client- with logos-

imported to Photoshop and saved as psd (checking that the background is transparent)

create imageprop in V11 (mac 10.3.4)

options: use mask, constant reflectivity, create plug-in, transparent color

color tolerance and mask contrast left at defaults

Viewed in final renderworks the background is still seen as light grey- which is a problem- because this needs to look like cut vinyl on glass.

My workaround has been making a lot of extruded polygons - but there must be a better way?

TIA

Ziska

[Dave Donley]

Hello Ziska:

Can you send me the file?

Does the black and white mask shown in the transparent color mask dialog look correct? I.e. the background is black?

[Ziska]

Dave

The lettering is white- the bg black- yes it looks correct.

It looks grey on the glass extrude.

Sending e-mail....

Ziska

[Dave Donley]

Hello again Ziska:

OK, I think I finally know what is going wrong here. It looks like the mask is created OK now. The reason why the letters disappear when you switch the color shader to Object Attribute has to do with the way the texturing uses the aspect ratio of the color shader. When the texture has a color shader that uses the same image as the mask everything lines up since they both have the same aspect ratio. When the Color shader is changed to Object Attribute, the mask is stretched to an aspect ratio of 1, since the color image isn't there anymore (the color shader determines the overall aspect ratio for the texture). Since the mask image's aspect ratio isn't 1 the letters get stretched vertically. That is one problem.

The other is that the origin of the default mapping is aligned with the lower-left corner of the mask image. Your mask image has a band of whitespace in the lower half with the letters starting in the upper left corner so the letters aren't showing on the extrude with the default mapping.

To get a mask with letters that show up and are proportioned correctly the mask image should be created square with the lettering aligned to the lower left corner. If you import this kind of image you shouldn't have to fiddle with the default mapping at all if the extruded rectangle has the lettering's aspect ratio. You should also be able to keep it using Perimeter mapping. The extrude should use a rectangle with same aspect ratio as the lettering, so that the lettering just fits in the rectangle. The texture size field should be set to equal the width of the extruded rectangle. If all these things are set this way you shouldn't have to modify the default mapping.

If you are using 11.0.1 the Attribute Mapping tool can help to adjust the offset and scale of the textures, but it doesn't work with Perimeter mapping, only Plane, Cylindrical, and Spherical mapping. I had to re-attach a color shader to the texture so that I could see the object to change it to Plane mapping and then use the Set By Face tool (on the far right) and clicked on the extrude's top face to put the mapping on the top. Then I could go out to the document window and use the Attribute Mapping tool on the extrude to adjust the offset and scale.

HTH,