Controling Halo Lamps

Can anyone tell me how to change the starting point of a halo spot lamp? I am having trouble getting the visible light from a par can to display properly. I want the light to emit from the inside of the can at the size of the opening instead of from a point of origin. :expressionless:

The link is 404.

I can only guess what you mean - well, you’d have to simply increase SpotSi :slight_smile:

Sorry about the 404. Maybe the link will work now. I don’t know why the image doesn’t display in the post.
It’s not the spot size. I’ve lowered the spotsi to get a more focused beam which is visible, and moved behind the can to the point where the light would be the correct size for the fixture at the gel frame. The halo/volume is visible from the point of the lightsource (behind the can) which is unacceptable. :frowning: Clip sta/end has no effect on the volume.

Hey. You could try setting it up like this:

Doing this I got it to look like this:

Sorry 'bout the quality of the first picture, hope it’s enough for you to get the point. Got the blend if you need it.

That’s what I was doing originally TurboG, but the problem with the configuration is that there is no control over the “light spread”. If the lightsource is set to the back of the fixture, the spot size has to be set at a fixed spread for the volume to look correct at the gel frame. In order to produce a narrower spread, the lightsource would need to move further behind the fixture for the diameter of the volume to be correct at the front of the fixture.

I’m considering trying to alfamap a cylinder to “fake” the volume effect and then setting a normal spotlight in the fixture to track it. That way if I want to make the volume wider or narrower I can modify the mesh and change the lightsource to match. I hope I’m being clear. 8)

Any more ideas?

I have absolutely no idea what your problem is, that render looks perfect to me…

intrr, my problem is this

Figure 1 would be okay, but if I want to make the light narrower as in figure 2, the diameter of the volume is not correct at the front of the fixture. To correct this I moved the light farther behind the fixture but the volume is visible from the spotlight origin as in figure 3.
Is there a way to change the starting point of the visible volume so the effect will look like figure 1 with a narrower beam as in figure 3? I don’t want to see the light behind the fixture, but I want to be able to control the diameter of the beam.

I hope this clears up any confusion.

Can you just increase or decrease the diameter of the can?

Yes, this could be done but it would look odd when set with other fixtures of different spreads. Besides, the whole purpose of this string is to determine how much control there is for the halo lamps and work arounds for control that is not available for the light directly. I am planning to model a complete theatrical stage (and animate it) eventually. The lighting system is a major part of the set and I need to find the limitations of what I can do, such as animating fixture movements, beam spreads with smoke moving through it, followspots, animated strobe flashes, gobos, etc. Right now this is just a light study. 8)