Prop Clip
Overview
Prop Clip refers to a series of techniques used to cause a physics object to clip (intersect) into a solid geometry (like a brush wall, static model or another physics object).
Clipped object behavior
When a physics prop is clipped into a solid geometry, it can move around freely withing said geometry, with some limitations. Occasionally, the game will put the prop into a sleep state, freezing it until something wakes it up (interacts with it). This is especially common when the prop is entirely submerged in a prop, and especially problematic as well, since interacting with said prop becomes impossible. When the prop is awake, the game will attempt to push it away from the wall with a constant velocity in a random intervals of time.
The exact reasons to this behavior are unknown and need to be investigated.
Types of Prop Clip
Showcase of different Corner Prop Clip methods and an example of usage presented by Nidboj132
Example of Held Push Prop Clip in Smooth Jazz 0 portals by Krzyhau
Showcase of Portal Prop Clip by Tyronis
There are multiple types of prop clips which differ in a method of clipping a prop into a solid geometry:
- Corner Prop Clip - a method which utilizes a faulty collision detection (details are unknown) to avoid colliding the prop with the edge/corner of the brush. So far, it has been proven possible only with the cubes. To execute it, a cube needs to collide with the corner of the brush without going into the brush. We can distinguish multiple types of corner prop clip depending on the orientation of the corner:
- Wall Corner Prop Clip - clipping a prop through the corner formed by two walls.
- Floor Corner Prop Clip - clipping a prop through the corner formed by a wall and a floor.
- Ceiling Prop Clip - a method of clipping a prop through a seam between two brushes. It is unknown how it works or whether it's relevant to the Corner Prop Clip.
- Held Push Prop Clip - clipping a prop by holding it and pushing it with another prop into a wall.
- Co-op Drop Prop Clip - a method taking advantage of co-op session using different held object controller, which gives the player a brief period of time to drop a prop inside a solid geometry. Weirdly enough, this method doesn't work in singleplayer, despite some props (like personality cores) using the same view-model based held object controller.
- Portal Prop Clip - a method of clipping which utilizes portals. In certain scenarios, it is possible to cause a held prop to teleport despite passing through the portal outside of its boundaries, causing it to teleport into the wall on the other side of a portal.
Usage
Since most of methods of Prop Clip require very precise setup or incredible luck, this tech has the most of usage in Least Portals.