Question Position space: None

Space "None" will bypass any automatic space convertion (when pluggin a port in local space to a world space system for instance) so it effectively considers the input is in the space of the system (as not conversion is performed)

 

Yes, none space is only a new mode for spaceable slot. If you choose None on a input slot from a block, then, the block won't apply any space conversion and implicitly use the same space than system.

This option isn't only used in block, you can use the operator "Add" with a spaceable type:

N.B.: In this gif the name of the operator "Position - Local" is supposed to be updated, we will register an issue ⏳

Indeed, the documentation should be updated and exhaustive about this behavior and usage, meanwhile, in case of operator, how it works:
- The output Space is chosen based on inputs Space
- There is a priority order, from highest to lowest priority, we have World, Local, None.
- If an input space doesn't match the output space, then, the input property is converted to output space before operation content.

For example, in that case:

We are mixing Local, World & None, the World Space is the highest priority.
Before the addition of A + B + C, we will have:
- The input A will be converted from Local To World.
- The input B won't be converted (World To World).
- The input C will be converted from None To World (which is a None Operation, it acts like C is a Vector3 or already in World).

Side notes:
- A particle system can't be in None space, we still have to specify how to render and update particles.
- The spawn system doesn't handle any space because it can feed values to a system in World or Local System.
- The input spaces in subgraph block content are expected to be in None Space, the usage defines the space.
- Since 2023.1.0a19, the expected space of an exposed property is available by script with VisualEffectAsset.GetExposedSpace