I take advantage of this post to know your habits and method when using O-rings in your assemblies.
How do you proceed? Is it a piece to create every time? A library room? configurable?
How do you draw an O-ring? a simple torus, corresponding to its dimensions in the free state? or a revolution of an oblong torus, to represent it in position in its throat?
The first solution allows you to easily manage references of library parts, but the display in the assembly is not perfect since the dimensions of the joint in the free state will make it appear "in the material".
The second solution allows for beautiful visualization in assemblies, but part management becomes difficult. An O-ring reference may have different mounting deformations...
In general, we do the basic version (so no distortion). And if it really bothers the customer, we consider the distorted version, where it's really visible.
We have the advantage of storing commercial parts with business.