Projection mapping with segments

Hello there,
I am quite a new-bie in vvvv and
I am a bit in trouble trying to finish up my final project which is based on vvvv.

My computer cannot bare the calibrate/runtime patch that Elliot Woods suggests for real-time calibration on a model, and I have been trying through the Projector Node, which as far as I can see, it will never match to the model properly…
So I wanted to ask if anybody has any suggestions for alternatives… I am even eager to map it all with segments, but as it is an amphitheatre, I need to have full control of the angles of the segment, plus I need to add a blend node on it so that I can add more layers to the final renderer…

for some reason, I cannot do it through homography, cause I cannot add more control points…

Does anybody have any suggestions?? it would be much appreciated!

CAn you post screenshots and or an example patch so we can see what it is your trying to do?

You can always oldschool make a picture where the projector is and use it as a mask overlay/mask to fake it all. But having a bad computer is not going to make it easier for you.

Like the Cat said, since we have not clear what your trouble is, or what you are mapping, it is hard to help you.

So I am using beta 30.2 x 86 vvvv, and I am trying to project on a model of a amphitheatre.
Two values come in vvvv from arduino, which is connected to a pulse sensor…

So, the scenario includes two pulse sensors connected to two separate computers. On each computer we have one projector connected, and both projectors are projecting on different parts of the amphitheatre.

I am attaching the patches I am working on, the final one is for the moment the ProjectorFINAL PATCH080913 2 on which the other patches are connected as subpatches.

I am stuck on the calibration part. I will send you also the calibrate patch I tried, if it helps,even though I do not see it happening…

If the calibration with the ProjectorFINAL PATCH080913 2 does not work, could you please show me how I could place segments all over the seatings of the amphitheatre? I need multiple reference points for the segments, which I cannot get through homography as I have heard… what should I do in this case?

Thank you very much and I am looking forward to your response.
I will also upload a photo of the mode in case it helps.

amphitheatre patches (770.5 kB)
photos (5.2 MB)

I see you have the x file of the model. And it seems pretty precise even if strangely triangulated…
I suggest you the Elliot routine described in his tutorials:


You’ll need [sites/all/modules/general/pubdlcnt/pubdlcnt.php?file=[/sites/default/files/uploads/](](]( - 31.05.12 by elliotwoods from

(is the previous release)

Take your time to understand what to do and you’ll map that model in 10min. (Maybe less)
(If the model is mm accurate)

PS: Be aware of the bug about the TAB key in keyboard node.
Can’t find it in the forum… Long story short if you press tab the output gives 1 and remain locked.
Don’t use the tab, just select the row from the table node.

I really suggest you to stick with Elliot OpenCV stuff

Good luck

@ Westbam,

what do you meanby saying "mask overlay/mask to fake it all. "
do you possibly have an example of this patch to send me here??
I have been trying the pic_mask here… IT seems to work, only thwe Renderer does not project the image once it is at projector’s window… Seems like a minor problem but has taken me a while to solve it…
Thanks a lot…!

It is a stupid old fashion 2D trick, take picture, make what you don need black (in photoshop) and use it as an overlay, it is how we used to map buildings, but you have your .X file, so forget about that.