Performance friendly way to render light rays?

Hi there,

is it possible to render light rays without a volumetric material?
The thing is that it takes far to long to render an animation with a volumetric material
(one frame about 20min on my gtx 660 with 250samples without volumetric about 10min)

so does anybody know a better way for light rays in an animation? :smiley:

A test render of the scene should be in the attachments.

Thanks so far :wink:


How about doing a plain 3D cylinder with a textured surface, with some animation of the UV-mapping upon that surface? Turn the alpha way down and add some blur. Comp this channel on top of what you have.

If the light beam should “shine on” something, create another layer with some spotlights, correctly positioned, shining on the surfaces. Grab a layer consisting only of those beams falling upon the surface. Comp these in, too.

Another way to make “flowing clouds” is to set up a scene consisting of a plane upon which a cloud-texture is being displayed. Put the cylinder in front of it and use it as a mask. Take this flowing-clouds texture and comp it in.

In each case, the technique is to first figure out “what would visually ‘look good’ and ‘appear believable’” Then, figure out a c-h-e-a-p way to produce an optical effect, for compositing into the frame, that will meet that qualification. Break down the overall requirement into smaller steps, e.g. “the beam of light” vs. “the light is falling-upon and reflecting-from something.”

yet you can create the rays straight into the compositor using “Sun Beams” node.


Hi HansEberhart,

try Sun Beams.