Alpha channels on image maps?!

Hi all

I’m trying to acheive a sprite type thing, by using planes as dupliverts from a particle emitter, and by mapping an image texture to them.

But I’v got a problem:
When I map an image (or movie) with a alpha channel to them (or just a normal plane which doesn’t move or anything), The renderer doen’t render the parts of the plane covered by the transparent part of the image as transparent.

Say you have a square plane in the view, with an image of a duck mapped to it, and that the duck pic is a targa of tiff, with only the duck opaque and the rest transparent. The rendered image is of a duck on a black backgrouns (which looks good), but if you only display the alpha of the rendered image, it is a white square on a black background, which is useless.

I’ve tried every combination of these settings:
Use image map alpha
map texture to colour and alpha
render with RGBA (into targa or alpha supporting mov file)

and so on

any help would be greatly appreaciated…

-Under Map To tab, map the image to Alpha (or Col & Alpha)
-Under the Material tab, turn A. to 0.0
-Under the Mirror Transp tab, turn on ZTransp
render out your image RGBA and it should work.

You have to understand the meaning of the “DVar” Button.

Thanks guys for your quick responses. The method works fine- and now I can have sprites (and the software render, with raytracing!!!).

A question for soylent_gr, what is the meaning of the DVar button?

The ONE downfall I’ve found to open source (and other free softwares), is that, while documentation is usually there, and is usually accurate, there isn’t the volume of reference documantation (ie what each button MEANS, as opposed to how to use it) that commercial titles have (probably because Alias or Adobe’s help writing dept is as big as there programming dept!!).

Having said that- my supreme thanks (and probably that of many others) goes out to anyone on forums such as this, who has the knowledge, time and inclination to help us Newbies out there.

One thing you don’t get with most commercial software (and can’t buy either) is the community and communal spirit.

So, how about it. soylent_gr?!

Thanks again

This is the destination value. If you click Alpha to on, every pixel with full intensity will get the Alpha value, that you have set with DVar. So if DVar is 1, all pixels with full intensity will get an alpha value of 1 (which is mostly not what you want, because Alpha 1 means completely opak). I you set DVar to 0, every pixels with full intensity will become transparent.

I have tried to explain that in greater detail on:

That’s a good point, though in this special case it may not hold completely true - I’ve invested quite some effort in the section about textures and the tutorials. One thing is of course the problem of distributing the most actual documentation (which is the one on mediawiki).

I’m more than glad if someone will make suggestions in how to improve the documentation.

With kind regards

Guys, and what about Yafray?
I have no problem with alpha in Blender Interlan Renderer. Example:

But in Yafray I cannot get a traced shadow, but the whole plane. Example:

How to get a shadow tracing the shape from the map - in Yafray? Anybody knows?