phantom_tool - tool.exe mod which prevents phantom BSP

[Conscars 66]

phantom_tool.exe is a modified tool.exe which will not produce phantom BSP when compiling JMS to scenario_structure_bsp tags with the structure command. It turns out the code for this has been in tool.exe the whole time, but was unused. This mod enables the hidden feature, but has the downside of producing slightly larger BSP tags. I still recommend you tackle the source of phantom BSP in your model (usually nearly-coplanar face warnings) and using regular tool.exe as the first attempt to remove it, then use phantom_tool.exe if that's not working.

 

How does this compare to Ghostbuster? Ghostbuster works on BSP tags directly rather than the JMS-to-BSP compilation. It is also prone to missing phantom BSP and can produce collision holes, so again use it as a tool of last resort and only if you do not have access to source JMS files.

 

This has been tested on a few maps with known phantom BSP, but let me know if you spot any issues. It also appears to fix BSP holes/leaks, which is another class of collision error where items or the player may fall through the map, but I'm not sure if this is just a side-effect of the BSP tree being different and if holes might still appear in other places. BSP holes can also be fixed by just altering triangulation in the area.

 

Usage

phantom_tool.exe is used exactly the same as tool.exe. Add the exe into your CE folder and compile structures:
phantom_tool.exe structure levels\test\tutorial tutorial

Download

phantom_tool.zip

Edited March 24, 2021 by Conscars
Fix broken link

[Vaporeon 189]

The core issue sounds like it was possibly an optimization gone wrong?

I wonder if it would be feasible to create another tool that edits the BSP to simplify the collision but in a safer way.

[Conscars 66]

Yea, I *think* the core issue is that ray collision tests against planes with a -1 back index (outside the map) make some assumptions about convex spaces which don't always hold under tool's normal structure compilation. This may have been done to reduce tag size, or to make projectile collision tests cheaper. You can have an "exposed" dividing plane with -1 back index that extends into the playable space depending on how the space got cut up. This exposed exterior plane is what phantom BSP is. The alternate code in tool seems to duplicate surfaces a bit more across sibling leaves, but I still don't fully understand how it chooses to do this. With more research, a community tool could probably do the same for BSP tags.

Edited March 8, 2021 by Conscars

[Kavawuvi 7,026]

Oh my goodness, this is really nice!

 

Personally, I don't really think it'd be a big deal to use it on everything unless it screws up something else. Maybe space might be a concern, but I don't think runtime cost will be that much different, if at all.

[Conscars 66]

On 3/9/2021 at 6:52 AM, Kavawuvi said:

Oh my goodness, this is really nice!

 

Personally, I don't really think it'd be a big deal to use it on everything unless it screws up something else. Maybe space might be a concern, but I don't think runtime cost will be that much different, if at all.

 

Apparently it failed to build a leaf map when compiling a TSC:E BSP, so we suspect it's limited to smaller BSPs.