Transparency in a texture?

[PolarBear]

Transparency in a texture?

I'm trying to do something perhaps a bit unusual. I want to create a plane then load a texture that is a gif with a transparency and place it on the plane so that when I render it the parts of the plane covered by the transparency in the gif are invisible and only the area of the plane that is cover be the image in the gif texture to be visible in the render. I've been tweaking the materials properties but every time I render the area of the plane that is suposed to be invisible shows up black. Any one have any suggestions on how I can accomplish this?

 

[irev]

No luck here

Hi PolarBear

Built a number of transparent gif files in PhotoShop, even ones with true transparent backgrounds. The material editor does show the gif transparent when the use alpha channel is checked in the material properties, but the transparent area always rendered black. Maybe someone else has a solution.

 

[PolarBear]

Thanks for trying. At least I know it's not just me. Anyone else?

By the way, Why is everybody here a site admin?

 

[Francois]

PolarBear, irev,

- a quick search in the forum would have brought you the solution. Anyway
- it depends on what you want to do
- the 1st image has : a *.png (with alpha) in the color section of the material + the "use alpha" switch in the transparency section + transparency intensy = 0
- the 2nd image has, in addition, a *.jpg in the transparency section. But alpha is off and transparency intensity = 1
- in both cases, the shadow type of the light (I used here a spotlight) has to be set on "raytrace+trans(parency)
- I also tried with a .gif to replace the .png and this is working too
- finally, this is with 3.1 but, if I recall correctly, I used to do this too with 2.6.1

 

[PolarBear]

PolarBear, irev,

- a quick search in the forum would have brought you the solution. Anyway

I did search the forum before posting. And After posting I went and read through the entire forum post by post while waiting for replies. No solution found.

And it's not working for me. I'm using 3.1 , the .png with alpha, Spotlight with shadow=raytracing+trans, Use Alpha checked, Intensity =0. Looks fine in the modeling window but renders black.

 

[Francois]

I did search the forum before posting. And After posting I went and read through the entire forum post by post while waiting for replies. No solution found.

I didn't want to be mean but a search with "transparency" brings back tons of answers (see the first couple of them in the image). The 7th from the top is pretty much the answer to your question. As I thought this was not really clear, I did a specific example just for you.

And it's not working for me. I'm using 3.1 , the .png with alpha, Spotlight with shadow=raytracing+trans, Use Alpha checked, Intensity =0. Looks fine in the modeling window but renders black.

Then you must be doing something else. Start with a fresh new file and a simple plane + cube as in my samples.
Are you sure the preview window is not in perspective mode looking at your object and the render camera pointing somewhere else ?

 

[PolarBear]

Another thing I'm doing is in the camera's properties I have the background color's opacity set to 0 because this for an OS X Icon and so I don't want there to be any backgrond in the finished icon.

 

[Francois]

Another thing I'm doing is in the camera's properties I have the background color's opacity set to 0 because this for an OS X Icon and so I don't want there to be any backgrond in the finished icon.

I don't see a relationship.
Does a simple render works ?
I think you should post your model (zipped jas file) to make this simpler.

 

[PolarBear]

I believe I have found the point at which it breaks. I found Martin's example file in this thread http://cheetah3d.de/forum/showthread.php?t=194&highlight=transparancy and tinkered with that first by unloading his texture and loading mine and then rendering. That worked. Then I set the opacity of his background color in his camera's properties to 0 and rendered and that worked. Then I deleted the the big giant box his scene was set in and rendered and suddenly it didn't work. It seems the transperancy is dependant on some object being behind it. When nothing is behind it. The transparent areas of the plane are rendered black. Since I am making an OS X icon. This is not an option for me. I can't have anything behind it. Any Ideas Martin?