Exporting MD3 models with tags

Exporting MD3 models

In this guide, I want to show you how I export models for use in modern Quake ports. MD3 is a 3D model format used by id Tech 3 engine and games based on it, as well as many other engines. Unlike older idTech model formats, it supports an extended amount of polygons and multiple surfaces on one mesh. It still uses simple vertex animation, but with float precision for vertices the wobble is almost invisible.

Blender does not support MD3 export by default, which means we need to get a proper addon. I recommend Blender BSP Importer by SomaZ. It is being actively developed, supports many extended features and is stable. So download addon, install it, click export, done?

Not so fast. The installation itself is simple. Download the add-on zip file from the Release page (or by clicking Code > Download ZIP). Open Blender. Go to Edit > Preferences > Add-ons. Click the Install... button on the top right and navigate to the zip you downloaded, then click Install Add-on. Tick the checkbox next to Import-Export: Import id Tech 3 BSP to enable the addon. Optionally add your base path and mod paths in the addons preferences if you want to import models as well. 

Now when you click File > Export you should see the ID3 MD3 (.md3) export option as well as a few others. 

MD3 Tags

Tags are some kind of local coordinate spaces, which are used to attach other models to them. This is a very important feature. For example you can add player cosmetics/armor by attaching a helmet to the character's head. Additionally, we could animate the player's hands and attach weapon models directly to the player's hands. This method also allows for the attachment of weapon accessories, like suppressors, without needing to create numerous separate models.

To do that using this addon we need to

1. Create an empty object with a name that starts with tag_* (for example tag_weapon)
2. Add Copy Location and Copy Rotation modifiers
3. Set Modifiers to copy your Armature and selected bone (for example hand_r)
4. To better  visualize it, import your weapon model, make the same modifier but this time set Target to your tag entity (tag_weapon).
5. Adjust tag to fit animation.
6. Now you need to bake animation. Disable weapon from rendering, select tag_weapon.
7. Click "Object > Animation > Bake Animation".
8. Click Enable visual keying, bake.
9. This should generate keyframes for your tag object. Now you are ready to export

Exporting

1. Select visible objects that you want to export.
2. Make sure all materials have a proper name (example: textures/player/player).
3. Click "File > Export > ID3 MD3 (.md3)"
4. Select proper modifiers (for example “Selected Only”)
5. Make sure to enter proper animation range. Each additional frame increases file size.
6. Export it and test it in the game.