I use alpha plane trees quite a bit, it saves render time. But I find that under certain conditions I get a faint square outline, slightly opaque, around the trees. I don't understand why this happens because I render them first against a white background and then flip the transprency over (in the alpha plane dialog box)when loading the image and alpha plane to leave just the tree. The background should therefore be totally transparent but it never is. Even if I prepare the tree in the scene I am to use them for, against the sky etc, it still produces the artefact (because the sky is colourful and therefore not transparent). But the same thing happens if I use a solid white. I often use the trees in silhouette backlighting. What am I doing wrong? I want a clean crisp tree outline! JoeBlack

If you use volumetric atmospheres with an alpha plane you always will get these faint outside lines. So, use alphas only with "normal" atmospheres. Guitta

Ah, i didn't know that. Thanks JoeBlack

Ive been having that problem with my waterfalls. Im going to do some experimenting to see if certain image formats reduce this. It shows up when using volumetric lights. It starts to dissapear after you turn the quality of the light down.

I know it sucks because you may not have the toys to do it but here's what I do- In Illustrator place your tree image OUTLINE - do not trace(it creates a billion splines)- around the image close enough to define the tree line. It doesn't have to be perfect. Make sure the path is in one piece and closed. Import to any 3d program that accepts AI files and convert the resulting spline to a mesh. Map the image per program's material editor as you would normally do and export it as 3ds obj etc. Bada-Bing - low poly 3d billboard that shouldn't interfere with nasty rays and volumes going through the scene. This really doesn't take long to do either. I think I spent 10 minutes on this one. Most 3d programs don't get that your simple planes alpha is supposed to be invisible so it hits it and returns the planes image as visible because thats actually what we're telling it to do. Hope this helps Bot

cool never thought of doing it that way. Thanks for sharing the info

Um i don't have Illustrator. Don't suppose Truespace can do that? JoeBlack

Not certain - I don't use Truespace. In general, any program you can put an image into and draw a spline around the image should do. You'll need to export the spline as a Vue readable file though(3ds, obj etc.) I use Illustrator because its easier - you could probably use Freehand or any vector based program that allows you to draw a vector outline and save it as something like a dxf or whatever. PS I don't think you have to outline the gaps in the middle (I've never needed to) of the trees or anything - just the top, bottom, left and right extents of the image. The rest should be okay.

Yea Truespace has a draw function, spline drawing and other functions. I can export as DXF and 3DS. I might give it a go. Cheers JoeBlack

Let us know how it goes so others looking at this thread (and I) get the info. Bot

OK I'm trying it now as I type but I'm not sure if I followed the instructions properly. I placed a rendered image of a fir tree as the background in Truespace; used the spline drawing tool to trace roughly around it; converted it to a variety of formats including COB, DXF and 3DS. Now what? What if I'd like to use a transparency in Vue? Otherwise it just looks solid and not tree-like. Also, once I've applied a transparency to it (one I had already made and thought would fit) I get strange artefacts surrounding the tree, even though I made sure the tree was exported as a single mesh and closed. Vue acts like it's multiple objects warning me if I apply a material to one object it'll be applied to all others, etc. Anyhow, I'll keep trying. JoeBlack BTW: I added your suggestion to the Eonsoftware forum

Kinda sounds like you have a spline that wasn't closed. It should be a single object. It may also be extraneous geometry was added when converting from the spline into a mesh object. I do it in 3ds - apply the bit maps and the alpha image in whatever program you're using so that it creates the uv mapping before importing it into Vue. In Max , I just put an Edit mesh modifier on it after I make it into a spline. That makes it into a plane the shape of the spline. Don't add any additional geometry though. Bot

PS Where did you post it? Could you leave a link? Thanks Bot