Thanks to Tomb Editor, it's now possible to easily create diagonal walls and steps. However, sometimes people are not aware of possible issues it can cause: every once in a while I see level builder who says there's a bug in Tomb Editor related to diagonal geometry.

However, Tomb Editor isn't the guilty here. The problem is, diagonal walls and steps were never even supposed to work in original TR engines, and the possibility of it is just a nifty trick we do with floordata collision. Sometimes it causes issues, because Core programmers never designed their code and level formats to accomodate for diagonal geometry.

This is the list of potential issues with diagonal walls and steps. It's also applicable to diagonal geometry generated with meta2tr.

**1. Portal flickering**
With setup above, you will get glitchy room clipping, if camera goes through the block with diagonal step on the ceiling (highlighted in red on the screenshot).

**Reason:** tomb4 renderer is not aware of diagonal geometry, and when camera goes through it, it treats diagonal step as a solid block and tries to clip out room above or below, which it counts as invisible.

**Solution:** don't use diagonal steps on portals or use certain measures to prevent camera from going through it.

**2. Grabbable diagonal wall**
If you make diagonal wall and raise floor section below Lara's jump height limit, she can grab non-diagonal wall sides.

**Reason:** historically TR engines use floordata hack to implement grabbable "hidden crevice" which is extensively used to place secrets: if at least one corner between floor and ceiling has space, all sides of this block become grabbable. Now, technically diagonal wall always has free space at one corner, and when you raise floor section on diagonal wall, engine incorrectly treats this as hidden crevice.

**Solution:** don't use diagonal walls with floor section raised below Lara's jump height, better lower ceiling sections if you need that.

**3. Other Lara collision issues**
You can encounter other minor Lara collision issues, such as incorrect angle correction during running, occasional lack of "wall smash" animations, various issues with sliding and depth detection nearby diagonal geometry. All of these bugs are also native tomb4 bugs and not related to Tomb Editor.

**Solution: **carefully use diagonal geometry above 2-click height and test it thoroughly.

**4. AI issues**
As you already can expect, AI fails badly on diagonal geometry as well for the very same reasons: tomb4 pathfinding is unaware of diagonal walls and steps.

**Solution:** exclude diagonal geometry blocks from pathfinding.

**5. Impossibility to grab and climb diagonal ledges**
This one doesn't need additional illustrations or explanations and well-known. The reason is the same why climbing and grabbing doesn't work on classic triangulated portals.