So you’ve heard of MadMapper Spacial Scanner function,
but you don’t know excatly what it is, or even how to use it.
I’ll explain that in this tutorial.
The Spacial Scanner allows you to use your projector as a scanner,
to actually capture, pixel by pixel, what your projector “sees”.
For this tutorial, you’ll need:
- a projector
- a Canon DSLR (see compatibility list)
Sometimes, being kitsch feels refreshing (esp. for the sake of a tutorial)
Here’s what the final mapping will look like (a radio-active garden gnome):
It was done in less that 10 minutes, this might keep you motivated
to read through all the next steps…
I picked up a plastic dwarf. (I had it already actually)
Put it somewhere in my office.
This is my setup by day:
I put a projector in front of it. I used an Acer K11 that has 300 lumens.
Noted the resolution, which was 1024 by 768 pixels.
Because I’m a bit of a cowboy, I set it on its side in order to make things needlessly more complicated, and to prove that the equations work even in extreme situations, being sure it would “shoot” the entire dwarf:
I placed my camera at around a 45 degree axis to the projector beam.
FYI, my DSLR is a Canon EOS 500D with a Sigma lens.
I set it up to shoot the scene a little bit wider to capture the full output of the projector.
I did set everything in Manual Mode:
- Manual Focus
- ISO 100 (less grain)
- 1/15s shutter speed. It has to be lower than 1/60, your projector’s refresh rate
These settings were the best for my scene. Yours might be a bit different.
According to my tests a white background is not ideal because it reflects too much light. Under-exposed pictures are better because you get less artifacts. Ambient light is bad because it competes with the light coming from the projector.
I launched MadMapper. Plugged my DSLR to my Mac using a USB cable
and started the Spacial Scanner function.
It all happened in one click (which is good!)…
Once plugged in, MadMapper shows a preview from your DSLR:
I clicked “Capture” to start the procedure.
What the program does is project a bunch of white patterns, aka Structured Lighting.
These are succesive white bars, such as:
Since the whole process is automated (remember ? just one click …),
I took the opportunity to make myself a cocktail, while waiting for the final result to be processed.
Then I saved the picture somewhere on my drive.
MadMapper also loads it automatically as a background in the preview output:
Note the little artifacts on the resulting picture due to the poor conditions of this tutorial, and to the reflective nature of the surfaces. Matte surfaces are ideal.
Next step was to load the resulting picture into Photoshop and do some selections.
I selected the interesting parts of the dwarf, made a new layer for each part and filled them with white:
Note that I rotated the whole canvas for extended lasso/magic wand pleasure. If you do so don’t forget to revert back to the original orientation when you are finished.
I saved each of the layers as a separate PNG file.
PNG is good because it retains transparency, aka alpha.
For the super lazy visualist, there’s a script in Photoshop to export all the layers as a separate file automatically: ‘File | Script | Export Layers to Files…’
Then I assigned each picture to a layer and set the normalize option for each one.
This had the effect of correctly scaling each layer provided your preview ratio is set to 4:3:
With everything ready so quickly, I sent Modul8′s output to MadMApper (cmd-Y).
Make sure the Syphon resolution is the same as your pictures and projector, in my case 1024 by 768 pixels.
You can check that in Modul8′s ‘Preferences | Misc | Syphon output’:
Switching to MadMapper, I set the media input to Modul8 by double clicking on it in the list:
Then I created one single Quad surface.
A little trick is to unzoom a little bit in the Preview output to display the whole stage and the created Quad will magically fit the stage:
Wow! Normally, everything fits perfectly.
Then I switched back to Modul8 and changed the color of each layer, added some auto-color effect and whatnot. Had fun. There are plenty of other ways to have fun. a cocktail is obviously a part of it.
It works seamlessly in MadMapper:
And in the true spirit of self-satisfaction of the quickly achieved video-mapping tutorial, a made myself a final cocktail.