Here is a collection of known issues with Wall Worm, 3ds Max and/or the Source Game Engine.
[FIXED] Blend Materials Crashing 3ds Max 2021
Many DirectX shaders are crashing 3ds Max 2021, including the Wall Worm Blend Materials
There is a regression in 3ds Max 2021 that causes Max to crash when using Wall Worm's DirectX shaders for displacements.
Running Function with Keyboard Shortcut Opens Docs URL
Some of the MacroScripts in Wall Worm now have a default secondary action when executed with the SHIFT key held down.
Information on why keyboard shortcuts using the SHIFT key open the online documents for the function rather than running the function.
Error When Updating Wall Worm
Some problems that can occur when updating Wall Worm and Wall Worm Pro, along with some workarounds.
Viewport Freezes in 3ds Max 2017+
Fix: Update to the latest NVidia drivers.
The Max viewport can freeze and become unresponsive with Nitrous in DX 11.
FGD Parser Problems
Details on known issues with the FGD parser in the free version of Wall Worm.
Exporting SMD/VTA with WW Pro with a Morpher Modifier
Sometimes WW Pro will have a problem exporting a model with a Morpher modifier if the normals cache is not being displayed properly.
Max Crashes When Applying a Modifier
3ds Max scripted modifiers crash when applied to objects if the keyboard shortcuts include any assignments to the backtick key.
Slow Closing File or 3ds Max
This problem is fixed with sculpt meshes created with WW 2.82+.
3ds Max seems to hang when closing a file with a large sculpt mesh.
Unknown Bitmap Filetypes Crash VMF Exporter
Do not use bitmap filetypes that Max doesn't know how to read.
Using unknown bitmap types on world geometry and displacements will crash the VMF Exporter. This currently happens if using VTFs in materials in 3ds Max 2013 since there is no VTF plugin yet.
Displacement Texture Scale Sometimes Incorrect
Understanding Displacement Blend Texture Scale
This page explains one cause for displacement materials to be scaled incorrectly in Source as well as the solution. You should use bitmaps of equal dimensions in both materials controlling the Blend material.