Assets for Visual Pinball Engine

Common assets for all render pipelines.

Setup

You'll need git LFS in order to use this repo. Install the extension if you don't already have. Then enable it before cloning the repo.

git lfs install
git clone https://github.com/VisualPinball/VisualPinball.Unity.AssetLibrary.git

Overview

We're trying to be in sync with vbousquet's pinball-parts repo. To facilitate this, we're splitting the library items the same way, so you'll find the same Blender files in this repo. However, since we also bake down details into normals, we don't use pinball-parts' original files, but our own.

These Blender files are our "source of truth", and are located in the src~ folder in each directory of the assets. They are, however, not what ends up being imported into Unity. For Unity, we're exporting the Blender files to FBX files, typically into even smaller chunks, to avoid having too much overhead.

Baking

Most of the Blender files have low-poly geometry which is then enhanced with modifiers, typically bevels. In Unity, we use the low-poly geometry. In order to export to FBX, we export without modifiers, another time with modifiers applied to a hi-poly FBX, and bake the hi-poly geometry into the normal map. However, sometimes, there are more complicated differences like screw threads, in which case we keep two versions (low-poly and hi-poly) in the Blender file, and toggle each version when exporting.

Materials

Most of the materials have been created in Substance Painter, which we also use for baking the normal map as well as a thickness map where needed. The resulting textures are kept in the same folder as the meshes, along with the Unity material and prefab.

Workflow

How to add or update items can vary depending on the asset, and will be specified in the next section. The principles are always the same:

• One Blender file may result in multiple exports. For example, Plastic Posts.blend exports to Plastic Posts and Plastic Spacers. The different exports are grouped by categories in the Blender file.
• Items of an FBX file all share the same material. There may be several materials because there are meshes with multiple material slots, but one material type is applied to all the items in the FBX with that material type.
• If a Blender file has complex geometry that is baked down that cannot be implemented purely with modifiers, there will be additional categories with low-poly and hi-poly meshes. These need to be toggled when exporting.

With that out of the way, here is a typical workflow for adding or updating items.

1. Update or add the Blender file with the asset. If it's an asset that doesn't exist in pinball-parts yet, contact vbousquet or create a pull request in his repo to add it there as well.
2. Select the low-poly items of the category you're going to export. Since they all use the same material, UV-unwrap them all together.
3. If the file has separate categories for low-poly and high-poly, hide the hi-poly category. With the items selected, export to FBX, and be sure to check Limit to: Selected Objects and uncheck Apply Modifers under Geometry. The exported file should be in the asset folder, not in src~.
4. Export the selected items as FBX again, this time with Apply Modifiers enabled, if available with the low-poly category hidden and the hi-poly category visible. The exported file should be in the src~ folder, suffixed with - Hipoly.
5. Open Substance Painter, import the low-poly FBX (or open your existing SSP file and update the project configuration). Bake the mesh maps, using the hi-poly FBX under high definition meshes. Do the texturing.
6. Export the textures into the asset folder. Sometimes, you'll additionally need to export the mesh maps, too.
7. If you've just updated an item, you're done. If you have added an item, open Unity and drag the low-poly FBX into the scene.
8. Unpack the prefab in the scene and assign the material to the new item. If you've created a new FBX and there is no material yet, create a new one named after your FBX and assign it the exported texture maps.
9. Drag the new item from the scene into your asset folder to create a new prefab.
10. Set the position of the prefab to (0,0,0) and the X-rotation to -90°.
11. Delete the game object you've added from the scene.
12. Add the prefab to the asset library and add the meta data (we will document how to apply meta data soon).
13. Commit and push the new or updated files in git.

Library

The library assets can be found at Assets/Library. We'll go through each of the curated assets with a short description about how to deal with them.

Posts

• Plastic Posts.blend contains both Plastic Posts and Plastic Spacers.
• Metal Posts.blend contains Metal Posts, Metal Hex Spacers and Metal Round Spacers.

Plastic Posts

• Source: Posts/src~/Plastic Posts.blend
• Reference: /Posts/Plastic Posts.blend
• Asset Folder: Posts/Plastic Posts
• Export: Select items in the Plastic Posts category. The only difference between hi-poly and low-poly are the modifiers.
• Material: We don't use an albedo texture for the plastic, because it should be easily customizable. The other maps aren't very important, but edgeglowplastic seems to work well.
• Notes: There are two materials, Plastic - Peg Red and Metal - Peg, which need to be renamed to Plastic and Metal respectively. Only the plastic needs any exported textures, the metal is generic. The plastic however needs a thickness map as well.

Plastic Spacers

• Source: Posts/src~/Plastic Posts.blend
• Reference: /Posts/Plastic Posts.blend
• Asset Folder: Posts/Plastic Spacers
• Export: Select items in the Plastic Spacers category. The only difference between hi-poly and low-poly are the modifiers.
• Material: We don't use an albedo texture for the plastic, because it should be easily customizable. The other maps aren't very important, but edgeglowplastic seems to work well.
• Notes: There are two materials, Plastic - Gray Glossy and Metal - Peg, which need to be renamed to Plastic and Metal respectively. Only the plastic needs any exported textures, the metal is generic.

Metal Posts

• Source: Posts/src~/Metal Posts.blend
• Reference: /Posts/Metal Posts.blend
• Asset Folder: Posts/Metal Posts
• Export: Select items in the Metal Posts category. Apart from the modifiers, we have a low-poly and hi-poly category that need to be toggled when exporting.
• Material: We currently use Steel Stained with Luminosity of Steel Base set to 0.55.
• Notes: There are two materials, Plastic - Sleeve Yellow and Metal - Peg, which need to be renamed to Plastic and Metal respectively. Both materials are exported to textures.

Metal Hex Spacers

• Source: Posts/src~/Metal Posts.blend
• Reference: /Posts/Metal Posts.blend
• Asset Folder: Posts/Metal Hex Spacers
• Export: Select items in the Hex Spacers category. Toggling modifiers is enough.
• Material: We currently use Steel Stained with Luminosity of Steel Base set to 0.55.
• Notes: Only one material - straight forward.

Metal Round Spacers

• Source: Posts/src~/Metal Posts.blend
• Reference: /Posts/Metal Posts.blend
• Asset Folder: Posts/Metal Round Spacers
• Export: Select items in the Round Spacers category. Toggling modifiers is enough.
• Material: We currently use Steel Stained with Luminosity of Steel Base set to 0.55.
• Notes: Only one material - straight forward.

Dependency Graph

Both the HDRP and URP packages have a dependency to this, however the main project maintains its own assets for now.

Credits

Most of the assets in this library are derivations of pinball-parts. We use the low-poly geometry of these assets, and bake them into normal maps.

License

Creative Commons Attribution-ShareAlike 4.0