MadMapper Spacial Scanner tutorial

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:
– MadMapper
– a projector
– a Canon DSLR (compatibility list on MadMapper website)

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):

Frightening ? Mwhahaha…
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:

Then, I put a projector in front of it.
(here, a Acer K11, 300 lumens, possibly one of the cheapest unit around)
Noted the resolution, which was 1024 (?!) by 768 pixels.
Because I’m a bit of a cowboy, I installed it on the side (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:

Placed my DSLR around (not necessarily exactly on the same axis as the projector, a 45 degrees axis might be fine as well).

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 that 1/60, your projector’s refresh rate)
– F3.5

These settings were the best for my scene, yours might differ a bit.
According to my tests, white background is not ideal because it reflects too much light. Under-exposed pictures are better, you get less artifacts. Ambient light is bad, it troubles the calculations.

Then launched MadMapper. Plugged my DSLR to my Mac using USB.
Then started the Spacial Scanner function.
It all happened in one click (which is good !)…

Once plugged, MadMapper shows a preview from your DSLR:

I clicked “Capture”, which had the effect of starting the automated procedure.
What the program does is projecting 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.
(mate is better)

Next step was to load the resulting picture in Photoshop and do some selection.
I rotoscoped the interesting parts of the dwarf, and made a new layer for each part, filled with white:

Note that I rotated the whole canvas, for an extended lasso/magic wand pleasure. If you do so don’t forget to revert back to the original orientation at the end.

I saved each of the layers as a separate PNG file.
PNG is good because it keeps transparency, aka alpha.
For the super lazy visualist, there’s a script in Photoshop to export all the layers as a separate file automatically (menu/file/script/export layers as file)

Then, launched Modul8, as placed each file in the Media bin:

Then I assigned each picture to a layer, while setting the normalize option.
This had the effect of scaling correctly each layer (provided your preview ratio is set to 4:3):

With everything ready so quickly, I sent Modul8’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:

Switched to MadMapper, and set the media input to Modul8 by double clicking 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 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).

Witnessed it worked seamlessly in MadMapper:

Finally took a picture of the final result:

And in a true spirit of self-satisfaction of the quickly achieved video-mapping tutorial, a made myself a final cocktail.