How to create a face scan type of effect

[stevesideas]

Basically where the face is front on and the scan lines go from top to bottom following the contours as if being scanned at a security device.

I'm assuming it is something to do with normals but I have no idea how to implement it.

[Dariusz Makowski (Dadal)]

U can use light with texture as projection to project laser scan lines on face. Then use texture in light. Or u can just use uvw projection of texture.

[super gnu]

or you could use a thin rectangular vraylight with the directional parameter and animate it moving over the face..

orr, a standard rectangular spotlight..you could even add some nice subtle max standard volumetrics to it to get a deeper effect
many options!

[stevesideas]

Yes, I was overthinking things about the normals. I've decided to use aftereffects and duplicate the face layer with a mask that is animated. Seems to do the job quite nicely. Thanks for the tips

[Paul Oblomov]

Do it in post Output position pass and ur done....

[hcgord]

I've got a similar thing I would like to achieve. I don't really understand the above solutions (other than the one I used and am stuck on).

I am simulating an industrial 3D scanner and they have a visible red laser light used for the geometry portion of the scanning. The scan line is actually a series of small dots at a specified spacing but at a distance it just looks like a single line. I am scanning boards (wood) in a sawmill application.

I'm using a Vray Light (direct) to get a nice thin line. It's simple and it works. The laser line follows the geometry as it should in real life. Problem is the line is hard to see because of the ambient light... Washed out red color. Very much like in real life!! I almost always have to reduce the light on the boards so they appear darker and the scan line shows up. Note that changing the multiplier of the light does not make the line more intense.

Is there a way to increase the intensity of the light without darkening the boards? I don't need to see the diffuse map below the laser but just really want a bright fully red (255,0,0) line. It won't look like real life but at least I will be able to see it. I noticed that if I change the Vray light from Color to Temperature then I can get really solid colors. Unfortunately I don't understand what's happening. I either get purple, yellow or white. Nothing of what is actually showing in the colored box.

Or can I somehow isolate the laser light (alpha channel, animated mask?) and add a laser line in post processing? How would I go about doing this?

Any help would be greatly appreciated.

Cheers

[Neilg]

^ make a copy of your scene, turn off gi and all lights apart from the laser one. maybe use a little environment fog to help with visibility, then add that render over the top of the other in screen mode.

[hcgord]

I'm thinking your meaning to composite the laser overtop of the main render? If so this is what I'm attempting right now and seems to work pretty well. I added a VrayLightSelect Render Element for my laser light. This gives me only the light for the laser which I can then composite in Premiere.