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Source Engine Collision Tools

by Theanine3D·Workflow

Images © Theanine3D. Used for product review; image policy.

Why we like it

Earns its place in the blender_extensions library by covering the full collision pipeline in one addon: several generation methods, a set of hull cleanup tools, and QC/QCI plus VMF output for Hammer, all under a GPL license.

What is Source Engine Collision Tools?

Source Engine Collision Tools is a Blender addon built for creating and optimizing the collision models used by Source Engine games, including Team Fortress 2, Garry's Mod and Left 4 Dead 2. It works best when combined with the Blender Source Tools, and its interface lives in the Object Properties tab on the right-hand side of the window.

The addon offers several ways to generate collision: by bisecting a model into sections, from a mesh's faces, from an object's rigged weights, from a UV map (turning each UV island into a separate hull), or via Blender's built-in Cell Fracture addon. Every generation method supports a Decimate Ratio setting to reduce the complexity of the result, and a Recommended Settings button can guess suitable values based on the active object.

Beyond generation, it includes hull cleanup tools for merging similar or thin hulls, removing buried hulls, and forcing convexity, plus output features that generate Source Engine QC and ragdoll QCI files, export hulls to Hammer .VMF brush solids, and update or clean existing VMF files.

Who is Source Engine Collision Tools best for?

Source Engine Collision Tools is best for blender artists preparing collision models for Source Engine games such as TF2, Garry's Mod and Left 4 Dead 2, particularly when working alongside the Blender Source Tools.

How much does Source Engine Collision Tools cost?

Source Engine Collision Tools is completely free to download and use.

Key features

  • Multiple collision generators: via Bisection (dividing the model into sections), from Faces, from rigged Weights (usable for Garry's Mod ragdoll physics meshes), via UV Map (each UV island becomes a separate hull), and via Fracture using Blender's built-in Cell Fracture addon
  • All Generate features support a Decimate Ratio setting to automatically reduce the complexity of the resulting collision model, plus a Recommended Settings button that guesses settings from the active object
  • Hull cleanup tools: Merge Adjacent Similars (based on face count and volume), Remove/Merge/Select Thin Hulls, Find/Remove Inside Hulls, and Force Convex
  • Split Up Collision Mesh into separate objects, with each part holding no more than 32 hulls (the limit can be customized)
  • Generate Source Engine QC files for compiling with batch tools such as Crowbar, with a QC Override system for custom commands like $scale or $surfaceprop, plus Ragdoll QCI generation with $collisionjoint lines built from your armature's bones
  • VMF tools: export hulls to Hammer .VMF as brush solids, Update VMF with split-up collision models, and Clean Duplicate Collision entries (phys_part)

Tags

#Source Engine#collision models#Blender addon#TF2#Garry's Mod#QC files#VMF#ragdoll

Frequently asked questions

Does Source Engine Collision Tools work with Blender 4.2?

Source Engine Collision Tools is compatible with Blender 4.2 LTS and newer, so if you're running that release or a later one the addon will work. It pairs best with the Blender Source Tools for a complete Source Engine export workflow. The current version is 3.2.0, released on 17 July 2024. Since compatibility is stated for 4.2 LTS and up, older Blender builds fall outside that range. Check the developer's GitHub page if you need specifics on a particular version.

Do I need the Cell Fracture addon for Source Engine Collision Tools?

Source Engine Collision Tools uses Blender's built-in Cell Fracture addon for its Generate Collision via Fracture feature, so you'll need to enable Cell Fracture in your Blender preferences before using that option. This generator is best used on individual props rather than whole scenes, and works best on fully sealed objects with no holes or non-manifold geometry. A Fracture Target setting controls how many hulls it aims to produce, so a target of 4 will try to split the model into four parts. The other generation methods do not require Cell Fracture.

Is Source Engine Collision Tools free to use?

Source Engine Collision Tools is listed as free in this catalog and is released under the GNU General Public License v3.0 or later. You can download it from the developer's GitHub page, where the source is also available. Because it's GPL-licensed, you're free to use and modify it under the terms of that license. For the most current licensing details, check the developer's page.

How does Source Engine Collision Tools create ragdoll collision meshes?

Source Engine Collision Tools can build ragdoll collision meshes with its Generate Collision from Weights feature, which creates a collision mesh based on each object's rigged weights and can be used to quickly create ragdoll physics meshes for Garry's Mod. It also includes a Generate Ragdoll QCI tool that produces a .QCI file for every rigged collision mesh, with $collisionjoint lines automatically generated from your armature's specific bones. You can then load that file from your main QC using the $include command.

Where is the Source Engine Collision Tools UI in Blender?

Source Engine Collision Tools places its UI in the Object Properties tab on the right-hand side of the Blender window. Its features are greyed out when no object is selected, so you'll need to select an object in the 3D Viewport first before the tools become available. From there you can reach the generation, hull cleanup, and QC or VMF export options the addon provides.

Alternatives to Source Engine Collision Tools

Also in Workflow for Blender.

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