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Reverse Designing a Gobo


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need to get a custom Gobo made that will project text. (telling the audience to silence their cell phones.) The problem is it will be shooting from a quite extreme angle and there will be significant distortio on the image. Can anyone think of a way to reverse design using VW, Spotlight or Renderworks a predistorted Gobo so when it hits at the angle it reads correctly?

Thanks in Advance,


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  • Vectorworks, Inc Employee

If your concern is the actual Gobo, just let the manufacturer know the details. I needed a Gobo that was basicaly a circular with text. I need the circle to be round and the text to be square. I ordered the Gobo from Apollo; I told them I was using a 19deg S4, the throw distance was x, the height was y and the image needed to be Z. They did the math and it was perfect.

If you want to try it in VW.

Type the text in a TrueType font.Select the text and run the menu command TrueType to Polyline.Extrude the polylineRotate 3D x?,y?,z? (you will need to do the math)If you want to make Gobo that you can project with RW, you should be able to do a solid subtraction with a "blank" Gobo and get the final result.Then consult the Spotlight manual on how to make the texture. You may need to convert the 3D back 2D polys before you make the texture.


Kevin LinzeyNNA

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My concern about this approach is it assumes the text i sthe same size when it leaves the nit as when it hits the wall.

My main problem is that part of the image is hitting the wall before other parts of the image due to the angle it is on.

Would a similar approach, but with a tapered extrude at the beam angle achieve this?

Thanks Again

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Use the image editing program of your choice to create a square image with your text. Use the create gobo texture command to create a gobo out of this image. Create a wall or an extrude in the same plane as the curtain you're projecting on. This will be your projection surface. Insert a gobo projector into your document. You want it to be in the inverse of where it would be in the real world. So If its 18' above the floor and 16' right of center then put it 18' below the floor and 16' left of center. What this will do is distort the image in opposition how it would be distorted in the real world.

Adjust the gobo projector and focus point heights etc until you get your image projected onto the wall surface the way you want.

Now switch to an elevation view that is looking directly flat on to the wall. Either export as an image file, or do a screen capture to grab the distorted image.

Voila, This is now a correctly skewed version of your text.

Julian Carr has a tool that does all of this keystoning stuff automagically. He developed it for one of the LDs for the Olypmics in Australia. (Remember that great big dodecahedron thing in the closing ceremonies) I believe they planned out their keystone corrections and cropping masks using VW and Julian's tool. I don't know if he's released it yet but it certainly couldn't hurt to ask.

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