Sprite Opacity Over Life

[ITdreamer]

Hello, friends

I render sprites. I apply shader with a texture, which I created in SHOPs. Render is OK. Alpha is good. But what I need is to make sprites become transparent over life. I tried to apply Color POP with ramp over life to particles, but the sprites Shader seems to overwrite the transparency, with the alpha of the texture. How can I solve this problem?

[ITdreamer]

It is very useful when you create smoke using sprites. You use a texture with its own alpha, and you need the opacity of the sprite change over life.

But I can't understand how to do that in Houdini.

Please help!

[ihab]

hey,

can you post a hip file, I think you did something wrong with the color pop. and i think you need to pass these variables explicitly to the sprite procedural. I don't know I haven't used sprites since h9 was released. I used it in h8 only. A hip is more than a thousand words

Cheers

[static]

In the material that is applied to your sprites, enter it and make sure you have a mantra:procedural sprite connected to your suboutput. Once done, add the attributes you want the shader to inherit to the Attributes tab in the geometry shader. In your case, you would add Alpha in order to have the shader inherit the particle opacity. Another example would be Cd, the color attribute.

[ITdreamer]

Here is a simple scene.

How can I make sprites become transparent over life?

Sprites_Test.hip

[MIguel P]

Here is a simple scene.

How can I make sprites become transparent over life?

Here it is.

You'll see the transparency in render.

Sprites_Test.hip

[ITdreamer]

[quote name='MIguel P

[ITdreamer]

MIguel

I tried to create the same scene from scratch, with the help of your example. But something is wrong. Your example works, my not. I can`t understand what is wrong. Looks like both examples are the same, but your works, and my doesn't work.

Please, help me to understand the problem.

Here is the new scene, which I've created from scratch, after I explored your example.

Sprites_Test_new.hip

Edited September 19, 2008 by ITdreamer

[ITdreamer]

I found it.

I've forgotten to add Alpha attribute in Mantra Sprite Procedural.

Now its OK.

Thanks to everybody!