| Here's a really nice tutorial from Marco Westveer at Lighthouse Holland support explaining how to make any object into a fixture for use with a virtual screen or any media feed.
You can use any object you have as a model in a model library as a 'fixture'.
The way to do that is to use an panel fixture in your scene, and use the object you want as the 'lens geometry' for that panel fixture.
This way, the object will be used as lens, and as such is lit up and can be used to attach a media feed to it.
To demonstrate, I will show you step by step how to do this.
First, you need to have a mode object to use. Here I created a 'triangle of triangles', with a few accents (a square and a sphere).
Notice that the square is on the left, and the sphere is on the right. When you use this objects as lens in front of the panel fixture, and to have the panel face towards you, the panel fixture is turned 180 degrees around the y-axis. This means that you have to keep this in mind when creating the model object, it has to be turned 180 degrees as well to get if facing correctly towards you.
(Later you will see that the sphere is actually on the left and the square on the right.)
Next, we have to make a scene with a panel fixture. First import the model object into the scene, and then insert a panel fixture into the scene. Since we are going to use the model object as lens means that the housing of the panel fixture will still be there. For this reason, we usually use a very small panel fixture for this purpose.
In the ShowDesigner module you can find it in the 'Other.spl' fixture library, as a 'LED Panel (for custom shape)', and in the 3D Visualizer module, you can find it in the Sidebar, in the 'LED' section, as a 'LED Panel (for custom shape)'.
In the ShowDesigner module, pick it, and open the properties window.
First go to the 'Color Mix' tab, and set the color to white (to turn on the panel).
Then open the 'Panel Shape' tab.
Change the selection from 'Default' to 'Object', and then select the model object from the drop-down list.
Now close the properties window, and you will see the object as lens of the fixture.
Notice that now, the sphere is on the left, and the square is on the right.
Now switch to the 3D Visualizer, attach a media feed, and see how the video is mapped to the mode object.