Drawing a rectangle or an ellipse with a stroke an no fill

Software Natron
1

I am very new to Natron. I have followed a set of basic tutorials and now I want to create and animate simple shapes.

What I want: draw a circle (or a rectangle) with just a stroke an no fill.

What I tried: used the Roto node to draw a rectangle or an ellipse, however the stroke parameters do not work for these options. I can only control the stroke when using the pencil tool. I successfully managed to make an ‘open rectangle’ with the pencil tool then animate the Visible portion.

Is there something really obvious that I am missing here?

Thank you!

2

There are not many drawing primitives in Natron, and if you feel this is an important feature you could make a feature requestissue on github to ask for “open ellipse” and “open rectangle” primitives. They are not difficult to add (ellipses in Natron are Beziers), but that would probably take two full days.
You could also do it using Python.
But for vector graphics, I would recommend using SVG, which can then be animated in Natron, see the GNUvolador sample project: Download Natron from SourceForge.net

3

Thank you for your answer and for you work!

I circumvented the issue by using SVGs as per your recommendation. I plan on making a plugin for this option as soon as I get more familiar with the tool.

Thanks!

4

Hello, it is easy to draw a stroke on any object. I will show this in terms of a simple circle:

  1. First Draw a Radial, set Softness to 0.
  2. Connect the Radial to Edge Detect Node.
  3. Create Merge Node, connect A to Edge Detect, mask to Radial. You will see a stroke on a circle.
  4. You can use Edge Extend Node to extend the stroke.

That’s all. You can also minus smaller circle from source circle to get the stroke. But it will not work for any object.
Here is ntp file: stroke.ntp (32.6 KB)

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