View Full Version : Rigging a Solar Laser

03 March 2009, 12:59 AM
I'm a new member, but a long time fan. I love everyone's work here and it's a big source for my inspiration. I've been using 3DS Max 7 for about 4 years, but I haven't really gotten into the rigging part of it. Most of my work is just testing out things and messing around.

Anyway, my latest project is what I like to call a Solar Laser. Basically I want to convert a solar power plant into a laser weapon that would be re-directed via satellites in geosynchronous. My design is just the basic idea right now, because I don't want to make anything really big if it's not going to work.

This is what I got the idea from. The mirrors combine the sun's light to heat water into steam power.

What I need to know is if there is a way to rig each individual mirror so that it follows the light source and reflects it to the top part of the tower. Any help would be greatly appreciated. I've looked for rigging tutorials on the web, but I haven't been able to find one that helps with my situation.

Thanks for your time.

03 March 2009, 01:31 AM
Use a look-at constraint. And bigger screenshots.

03 March 2009, 01:55 AM
If you want all of the mirrors to reflect sunlight onto the same point, each mirror would have to look at a point which is at an angle halfway between the sun and the target. To put that another way you need to bisect the angle made by sun>mirror>target.

So make sure to add both the target and the sun to the constraint at 50%, and I *think* that should bisect it.

03 March 2009, 02:27 AM
I just tried that, and it didn't work as expected.

The weighting of the two targets seems proportional to the distance of those targets, so if you move the "sun" further away while keeping the angle the same, the angle of the mirror still changes.

I don't know why the look at constraint takes the distance into account, but it seems to.

I also tried orientation constraint with two targets, but that resulted in some flipping, which I frankly don't understand.

03 March 2009, 02:47 AM
Okay, I've been trying various things, since I'm interested in heliostats too, and here's how I got it to work:

1) Made mirror, sun and target objects.
2) Made two long thin 3x3x1 boxes of the same length with look at constraints to point them to the sun and target respectively.
3) Made two dummy objects and stuck them onto the central faces at the ends of the two long boxes with attach constraint.
4) Added a look at constraint to the mirror with both dummy objects as targets (50% weight each).

When you move the sun, the long box looks at it and the dummy stays stuck to moving end of the box, then the mirror looks at the dummy instead of the sun.

The length of the boxes keeps the look at dummies at constant distance from the mirror, forcing the mirror's look at constraint to act as expected.

I doubt this is the "right" way to do it, but I coudn't see a way to override the distance weighting on the look at consraints, so I just worked round it.

03 March 2009, 03:20 AM
Thanks a bunch! I'm trying it out right now.

03 March 2009, 03:56 PM
When i just split the look at constraint between the sun and the tower, it seems to work fine no matter how far away they are... I just set the XYZ orientation and alignments to Z for the mirrors and it did what I wanted it to.

Here's what I got after messing with it for a while.

:bowdown: Thanks for the help. Now I can start making the mounts and stylize everything. :buttrock:

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03 March 2009, 03:56 PM
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