create dashed line around Mocha mask

I use an expression to copy the mask. Just converting a Mocha mask to a shape-layer path takes about one minute. Make sure the layer is named and visible in Mocha AE, select Visible Paths, create AE Masks, set the mask to none, start a new shape layer with the pen tool, click once, type "p" in the search timeline field to reveal the mask, with the Links and Columns visible, drag the pickwhip from Shape Layer 1/Contents/Shape 1/Path 1/Path to the Mask on the Mocha layer.

Then it is just a matter of adjusting the Stroke/Dash and Gap settings in the shape layer.

The spline in Mocha should not have any keyframes, or the dashes will move around as the mask path changes size.

If your tracking includes more than translation (scale, rotation, perspective). You can set the surface to the whole frame on the first frame of the comp, then apply. Corner Pin Tracking to the shape layer.

Step 1: Copy the Mask Path

1. Select the layer with the mask you want to copy in the timeline.
2. Twirl down the layer to reveal its properties.
3. Twirl down the "Masks" section to reveal the mask properties.
4. Select the mask path by clicking on the "Mask Path" property.

Step 2: Copy the Mask Path

1. Right-click (or Ctrl+click on Mac) on the mask path property.
2. Select "Copy" from the context menu. This will copy the mask path to your clipboard.

Step 3: Create a Shape Layer

1. Create a new shape layer by going to the "Layer" menu, selecting "New," and then choosing "Shape Layer."
2. Select the shape layer in the timeline.

Step 4: Paste the Mask Path onto the Shape Layer

1. Twirl down the shape layer to reveal its properties.
2. Twirl down the "Contents" section to reveal the shape properties.
3. Add a new "Path" property by clicking the "Add" button next to "Contents."
4. Select the newly added "Path" property.

Step 5: Paste and Convert the Mask Path

1. Right-click (or Ctrl+click on Mac) on the "Path" property you added to the shape layer.
2. Select "Paste" from the context menu. This will paste the mask path you copied from the original layer.
3. The pasted mask path might appear as a Bezier path, which is not directly compatible with the shape layer's path format. To convert it, right-click (or Ctrl+click on Mac) on the path's name and select "Convert To Bezier Path."

Step 6: Convert to Dashed Stroke

1. With the shape layer's path selected, go to the "Stroke" section under the "Contents" property.
2. Enable the "Dashes" option by clicking the stopwatch icon next to it to add keyframes.
3. Adjust the "Dash" and "Gap" values to control the dash pattern. For example, you can set "Dash" to control the length of the dashes and "Gap" to control the spacing between them.
4. You can also add keyframes to the "Offset" property to animate the position of the dashes along the path if desired.

Step 7: Adjust as Needed

1. Scrub through the timeline to see how the shape layer's dashed stroke path looks.
2. You can adjust the timing, size, or any other properties of the shape layer to fine-tune the effect.
3. You can also add additional shape layers, effects, or animations to enhance the visual result.

That's it! You've now successfully copied a mask path from one layer and pasted it onto a shape layer as a dashed stroke.