Image mapped light beam projected on clouds...?

[pokoy]

I have a request here which I'm currently trying to solve.

I want to look at a cloud layer from a camera and want a light beam to be projected from a different position. The beam has to be colored via an image map.

Am I right that the only solution would be to:

- create a geometry with an opening
- put another flat plane geometry into the opening, create a semi transparent material with the image mapped onto it for this plane
- put a light behind the geometry and crank it up
- place and rotate the whole 'projector' and hope that it works

Ideally, I'd like to be able to create a light, specify a cone so it becomes a spotlight and use an image projection for the light color. However, I can't seem to find an option to tint a light's color via an image and the only light that's available in TG2 is a point light shining uniformly in all directions.

I have looked around for a solution but didn't find anything. Any ideas?

[zaxxon]

A spotlight light type would be a nice addition to T2. I'm looking forward to the advanced folks weighing in on this one.

[pokoy]

I managed to get the thing I had in mind with the description posted above but I have a question:

I have a flat plane in front of the tube where the light is located. This plane has a default shader with an image in the opacity slot so it serves as a mask for my light - this works fine. However, even if the map has greytones, they get mapped to 0 or 100%. I cannot produce a gradient in the material's opacity, it's always either black or white. The funny thing is, it gets completely transparent when opacity's value is at .49999 and gets opaque when set 0.50001 - I don't know what's causing this but there's literally no space left to achieve semi-opaque effects.

Also, it seems there's no way to tint opacity. Since I cannot get any 50% value in the opacity, using diffuse for tinting opacity doesn't have any effect.

Is there any other way to achieve image-based opacity or transparency? If not, is there a way to make it accept gradients and tint opacity in the diffuse material?

I'd be very grateful for any insights, I have a request here where I need to use this effect and I'd like to do it in TG.

[j meyer]

As for the opacity behaviour,that's the way it is in TG2 unfortunately.
There is a workaround,though.You should be able to use the method
that works for airplane propellers.A watershader connected to a surface
layers child input,which is then masked by an image shader.For more
details,please use the search function,the method has been described
in depth a few times already.

[pokoy]

Many thanks for the info, seems that this workflow could indeed solve my problem. I'll try later.

Hope there will be updates to the materials so they're doing what you'd expect when mapping opacity.

[N810]

Soooo...

your tying to make the Bat siginal ?   

[pokoy]

Haha, I know there's not much need for this kind of effect outside of Batman productions, rest assured it's not the case here