shadow silhoutte

i am trying to make low poly tree and humans using planes with textures of the colour image and another with the black/white image of the same. though i have achieved making only the picture stand out with the black part transparent…the shadow is always rectangular.i have trashadow enabled for the plane receiving the shadows. i am using tga images. where am i going wrong …i have tried all tutorials. thanx in advance

You have turned on Ray Tracing in the Scene settings? And also you need to turn on Ray shadows for your lamps.

thanx 4 the reply…will definitely try the solution…but am confused @ raytracing in scene and yes the sunlight has ray shadow turned on.

Basically the only way to get traceable shadows is with ratracing. Z-trans will only give you the square you mentioned in the first post.

Let’s see, Scene Settings [F10] on the Render Tab has a button to turn Rays on,
Lamp shadows to Ray [F5] (select the lamp first of course),
Material Shaders to TraShad [F5] (select the object first),
Ray Transp in MirrorTransp tab [F5],
. . I think that’s all. : )
These all have to be turned on to get the alpha map to cast.

did exactly as u said and it happened:D thanx a lot. one last question thought:o, when i render with yafray the shadow is rectangular and when rendered with blender internal, it casts the exact sillhoutte but the image is blurred. i am using tga. what type should i use with yafray or with blender internal?

The current version of Yafray can’t acutally cast alpha map shadows. One of the reasons I don’t use the engine.

As for the image format you use in blender, it doesn’t really matter all that much, as long as you’re using a file type that blender can read. The alpha channel is calculated by levels of gray. Depending on whether you set material alpha to 0 and use the bitmap to add or whether you use the bitmap to subtract, black will subtract (or add) to the materials transparency and white will add (or subtract).

The reason you’re getting variable levels of transparency is because the bitmap isn’t entirely black and white (is that what you mean by blurry?). One method you can try to clean that up is to put the alpha map in seperate texture channel, turn the NoRGB button ON in the MapTo tab of the Materials buttons [F5], and turn Col off. Then in the texture buttons, there where you add the bitmap, you can play with brightness and contrast on the Colors tab. Turn contrast up to decrease the levels of gray etc. etc. Or in GIMP of course.

thanx a lot …a lot of doubts did get cleared up…maybe this issue should be posted to yafray developers to include in the next release. thanx again