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Qlab 3 – Projector Alignment and Mapping

Qlab 3 – Projector Alignment and Mapping

This Qlab show was created for a small dance concert at the University at Buffalo called Zodique Dance Emsemble. I took the role on this show as systems technician and programmer. The projection surface was 4 white ” Streched Sails” which spanned a 40′ black back drop.


I used two wide lens Sanyo projectors side by side with no overlap. Total surface resolution was 1600X600.

Grid setup



I used the Qlab alignment grid by checking the boxes saying grid. This grid makes it easy to align two projectors by just matching the grids. By slowly adjusting the projector feet, I aligned the two projectors together where they meet.

Due to a space constraint we could not have the projectors exactly in the middle of their own projection surface, meaning the images perceptive was skewed. Qlab has a way to fix this with corner-pins.


Nudging the corner-pins allows you to make the grid square and this mean your content won’t be displayed funky.

After adjusting the corner pins, we can accurately mask out the negative space of the sails. Qlab does not have an on-board masking tool, just the ability to apply a mask. I saved the grid image and loaded up Gimp to create a mask. Using the grid on stage as a reference I mapped out the positions of all the negative space and applied a gradient to all of the edges that would have otherwise shown. The final product looked like this:Mask grid

Quick tip: If you save the image and apply it you can make edits and reexport and Qlab will automatically refresh with the update.

After applying the mask to the surface in Qlab, I loaded an image to see the result.


Everything lined up beautifully, There was a visible seam between the two projectors due to the age of them. There was a weird color green purple color gradient that couldn’t be color corrected. If I had to do this project again I would overlap the projectors to try to get rid of the seam.

A Reflection on the Process of Creation.

The first step for me is to get motivated.
If I can find a reason to get excited to start something the next steps become so much easier. This is usually a moment in a show that catches my imagination while I read it, or even trying to solve the puzzles that the playwright gives us. Such as in Urinetown, I found that my motivation for the show was finding out what made each side tick.

The second step is to gain my own direction.
Once I have solved the issue of getting motivated I need to find a problem to solve. I can usually do this by defining parameters by which to contain the design, this creates an isolated problem in which I can work from many directions to find a solution. To define these parameters I like to break down ideas in the show   into one concise, poetic statement that defines some aspect of the show (action, mood, themes). I can use this as a grounding for my view of the show while talking to designers and directors.

These two steps lead to a great place jumping off point to create any kind of design. It boils down the show to the essence of what is happening to constrain it to the text, while be flexible enough for the director to make decisions on how the overall productions will look.

I have found an issue with this beginning process, I will create an analogy within the concise summary statement that is difficult to alter if the director views the show fundamentally different than I, which of course plays into my natural stubbornness.


Above and beyond the Arduino

There is a lot of hype about the Arduino in the theatrical world right now. The open source microprocessor provides a platform to base new design ideas and different solutions for old problems like triggering sound effects on an action. The Arduino allows for electronics that can be completely customizable to a large extent, and is very affordable, however at the lower price it starts to suffer from functional shortcomings.

First and foremost being memory. The chip can only hold so much information on it, and this isn’t just how large the program uploaded is, but also the buffers and allocated memory that the program needs to run. To make an LED blink is a simple program, however when we get into more complicated actions, such as communicating through midi or DMX the program becomes much more complex and needs to hold large amounts of information.

Secondly, the timers and the logic has some latency problems. The timers can only be so accurate and when pushing the processor the it tends to slow down in its computation, like an computer.

New solutions are emerging however, the Raspberry pi (http://www.raspberrypi.org/) is the next step. This board is more like a computer. It has a graphic user interface and allows for USB connections and ethernet connections built in. The board boasts a better processor, better networking capabilities, and easier integration with store bought technology.

These both have their Pros and Cons, but in a world that is becoming more integrated with technology and where more people are willing to learn rather than buy, i foresee these boards become very powerful, very quickly, and having many more uses in theater than we know now.