Blackmagic Forum

I love the controls that come with the default rectangle and ellipse masks.

However, there are many times where I want to do something like animating the width of a rectangle, but I need it to start from somewhere other than the center of the shape. I've looked everywhere and I can't see any way to change the anchor point of the mask.

Is this just a limitation of Fusion or am I missing something?

You're not missing anything. This is a limitation of Fusion at this point in time.

You could give the macro at this link a try. I don't know if it works with masks, but it does work with images.

https://www.steakunderwater.com/wesuckl ... 263#p25263

I was afraid of that. But I really appreciate the link. I'll look into the Marco. Thanks!

I recently tried Nuke for the first time, and one of the small things I liked was that with the Rectangle I had the option to expand any edge independently, or adjust from the centre by holding a modifier. It achieves this by defining the rectangle with four numbers, defining the X,Y coordinates of its bottom-left and top-right points.

Anyway, an alternative in Fusion would be to create a Polygon node, then with the Polygon selected, right-click in the Viewer and at the bottom of the context menu expand "Polygon1:Polyline" and choose Create -> Rectangle.

You'll get a popup in which you can specify the size in Fusion's usual 0-1 scale:


You can use that to define its size, or just click OK on the defaults and alter it later.

Now you have a standard Polygon defining a perfect rectangle. It defaults to animated, so remember it'll add its first keyframe on whatever frame you're on when you create it. You can now select any two points in the viewer to move any edge independently.

Or, for more precise control, select all points and Publish them (available in the right-click Context menu, and as an icon in the Polygon viewer menu), which will give you four X/Y co-ordinates in the Polygon node which you can use modifiers on, Connect To things, or just see for reference as to what area your rectangular polygon is defining. With the points published like this, the Polygon is defined in a similar way to Nuke's rectangle - albeit using twice as many data points to do it.

Polygon defining a rectangle with its four points Published: