OpenGL Object Transparency?

[trashcan]

I have a few extruded planes and they have a texture applied at 50% opacity. It renders properly in Renderworks, but I can't see the transparency in OpenGL. Is there a way to turn that on in OpenGL or no? 

[markdd]

You should be able to see transparency in OpenGL without any particular settings that I can think of. Your object will need a texture with Transparency enabled though.

Edited May 25, 2020 by markdd

[Pat Stanford]

Opacity only applies to 2D Objects. For 3D objects (including extruded planes) you have to use a texture with Transparency.

[trashcan]

Of course it works as expected now. Vectorworks relaunch solved it. 😄 / ☹️

[trashcan]

This is driving me nuts again. 

 

Pyramid is supposed to be transparent:

 

Texture details:

 

Class details:

 

Pyramid should be transparent in OpenGL, but appears to only show as transparent using a RW style (I.e., final quality):

 

How do I get this to work with Open GL again? Or... is this a bug. Have restarted VWX etc. 

 

 

[Pat Stanford]

I can't get transparency by color to work in OpenGL either. Plain transparency and Glass transparency do work.

 

@Dan JCan you comment?

[trashcan]

@Pat Stanford thanks for checking on that. Glass and plain both work as expected - so the hacky workaround is to use one of those two to see it in Open GL and then re-assign the actual texture to the class when rendering if you want to use the color method for transparency. 

[Andy Broomell]

Are you mixing a color into the transparency?  If you're only keeping the color set to white, then you might a well just use Plain transparency instead.

 

Also, one difference to note between the two methods is that the percentages are reversed - for one, fully opaque is 0% and for the other, fully opaque is 100%. But once you inverse the numbers, the transparency amount works the same between the two (when the color is set to white).

 

 

Edited July 2, 2020 by Andy Broomell

[Pat Stanford]

Andy, maybe you can clarify Transparency by Color for us.

 

I make a 3D object and pick a color from the color picker. I think create a new texture and pick the same color for the transparency. I set the percentage to 50%.

 

In OpenGL I get a fully opaque object with zero transparency. Set the transparency to Plain and it works as expected. Rendering in Renderworks also works using the texture set to Transparency by Color.

 

Is the Transparency by Color only impacting pixels that happen to have exactly the correct shade in the rendered image? Or am I missing something else?

[Andy Broomell]

Honestly I don't use Color transparency much, and same as you guys I find that it doesn't show up in OpenGL.

 

Color transparency is not choosing a color to be transparent. Rather, this option blends an additional color into the object when rendered. For example, the two objects below have the same "Color" (blue), but the one on the right has the Color Transparency set to a yellow color.

 

 

Using white in the Color Transparency options has no additional blending effect.

 

(At least this is my understanding of it; if anyone has more experience I'd be curious to here how it's used).