Tracking masking

I would like to know is is possible to mask things out like a tree for example when you are do camera tracking. Like in this video where the building is behind the trees.

Masks are not yet supported within the tracker. However you can use masks when compositing, if that’s what you mean?

You can use a Bezier Curve to mask and if the new one has object tracking couldn’t you set the Curve to follow? I don’t know for sure since I have not done much with Object Tracking at all.

I’ve been working on a project that needed this done for about three weeks now. I’m not a compositing guru, but I finally figured it out.

Look up some tutorials on the the roto-bezier add on. Basically, the add on lets you create a bezier shape that you can fit to the object you are trying to mask. The add-on actually allows you to add keyframes while in edit mode. So you mask your object in one frame, then insert a keyframe. Go the the next frame, move the bezier handles around to fit your object, and then insert another frame. So on and so forth.

It really doesn’t take long to figure out, but I had to learn more about alpha-over a bit more. And with this method, the edges that you mask are a bit sharp. I’m still trying to figure out how I can gently blur the edges of the mask…

Here’s a single low-res image that I have tracked and rotoscoped:

I’ll be happy to share with you what I can, if this is what you are looking for. Just let me know.

Certainly you could animate a mask within blender using object tracking (which is scheduled for release with 2.62, i.e. very soon). However unless your mask is 3D it will not help you because small angle changes on rigid objects will produce view variations that will throw your mask off. With non rigid objects (e.g. people) it is even worse.

As mentioned before RotoBezier addon is the way to go. Rotoing the mask most likely be less painful than constructing an accurate 3D mask for all but the most simple of geometries.

Yes please this exactly what I am looking for.

I have done some RotoScoping already. Though I found some tutorials that have a very effective way of doing it. It is not in blender but you can use the idea of Shapes. Its in this Video.

Oh and Dancerchris In theory there may be a way to prevent the view variations. Specially since you still make the Bezeir mask Though you may be right but I never give up on an idea that is how new things are learned. Though like with many the most thing learned is ways it won’t work. Yet there is times of hey that worked. So Thanks for the input. I will look at that and see if I can find any way to prevent that and still use the 2D curve. Any way I Hope the Tutorial I posted helps.

I have not spent much time in the forums over the past few years. I’ve forgotten how much you can pick up in just a short amount of time. Software special- that link to the YouTube video was awesome. To be honest, I had never even thought of taking an object out of one video and putting it into another. Like reverse green-screening. Very cool, and the method he used with shapes was pretty cool as well.

Konrad- it was painful, but I first started using the Rotoscoping Addon after watching Christorpher Barrett’s tutorial over at It was an afternoon of watching and diddling but I finally got a grasp of how to incorporate rotoscoping in my workflow, and how to do it quickly.

Once you’ve rotoscoped your footage, drop me a line and I’ll try to walk you through the compositing tricks I found.