Creating Ingame Models
This guide is intended to teach you how to get models for units to show up in the game. This is also applicable to other meshes such as trees, rocks, props and projectiles. We will only be covering aspects of modelling specific to Supcom, and cover some common mistakes when dealing with Supcoms specifics.
- A knowledge of modelling - this guide will show the supcom-specific aspects of making the model. If you are new to modelling in general you should pick a software of your choice and become profficient in that first.
- Blender or 3DSMax - Forged Alliance uses a proprietary mesh file format, and there are custom exporters written for these two programs. In our example, we will be using Blender to export the model for the game.
- The appropriate Supcom exporter for the above program. The Blender version can be found here.
Making The Model
While making your model, it is good to plan ahead so that you can save yourself time when it comes to unwrapping and texturing it later, as well as how it will move, if needed. To help guide us through the process we will be following the development of the T3 ASF for the Nomads faction, a custom faction added in a mod to Supcom.
The idea of the unit was worked out beforehand, and a complexity was kept in mind - Supcom models are low poly, so making the models with as few polygons as needed ensures that it wont suffer from performance issues, while not compromising on quality beforehand. To get an idea of how many polygons to use, export some models with similar uses from the game and check how many they have.
- Supcom uses Tri-based geometry, and does not support bezier curves, quads or solid geometry. So we will be using simple flat surfaces for the model.
- In our case, the ASF of the other factions have 300-1100 vertices depending on the faction, with Seraphim being the most complex. So we don't want to end up with more complexity than that.
- We know that our unit is going to be symmetrical, so we will be modelling only half of it and then duplicating it later, so that the UV unwrapping process is easier. To aid this we are splitting it in half early on in the process, and know which parts to keep identical in advance, such as its 4 wings.
The model needs to be unwrapped so that it can be textured. UV unwrapping is not covered in this guide, but there are some considerations:
- Supcom uses one square texture per mesh, so when unwrapping ensure that all the UV faces are in the same material.
- Typical texture sizes are 256x256 - 1024x1024. Lower for projectiles. In our case we will be using a 512x512 texture. Larger textures cause the game to slow down while loading them so they should be kept as small as possible.
- Maximising the use of the texture is strongly encouraged, so designing units where textures are reused by faces, symmetrical geometry and culling uneeded faces is encouraged.
The basic unwrapping process is as follows:
- Start with a model that has finished geometry as will be used in game.
- Remove all faces that will be sharing texture coordinates, so that only one instance of each remains.
- Unwrap all the faces in the left over model. Use simple unwrapping to ensure that the UV islands are not warped. This is especially important for hard surfaces.
- Arrange all the islands in a horizontal line, in order of texture priority. The more visible faces will be larger and so should be placed first to ensure they have enough space.
- Scale all the islands so that they would all roughly fit on the texture space.
- If the model has treads (or other scrolling textures!), place them now according to the specification on the texture.
- Arrange the islands on the texture space, starting with the highest priority islands.
- When placing, ensure that there is a 2px gap between the islands, and a 1px gap between the islands and the edge of the texture to avoid colours bleeding over.
- When placing, ensure that the most important edges of the UV islands are aligned orthogonally to minimise edge artifacts.
- Once all textures are placed, duplicate the model geometry that was removed previously. The UV islands will be shared automatically.
- Supcom uses point bones that have an orientation, but no length. For this reason they may appear somewhat strange in Blender, whose bones also have a length. This is not an issue however.
- The model needs to be rigged correctly, and all the bones should have a unique name. The base bone name will be what the exporter exports the mesh file as, but it can be renamed.
- Bones with more than one parent are in theory supported by the engine but so far only single parent bones have been made to work.
Animations are supported by supcom, but exporting them again makes them hard to edit
Supcom has a custom texture set that has some quirks unique to the game. The textures used depend on the shader - for example units have a different set from projectiles, however the overall principles are the same.
All textures should be made using the DTX5 format, for DDS textures. They can be in theory any size, but sizes larger than 1024x1024 are not recommended. The textures should be square, but dont have to be.
For units, the texture set is as follows (the shader is NOT physically based):
- Albedo - This is the base colour the unit uses. (Diffuse) It has 3 channels, R,G,B. When converting from a PBR workflow, combining base colour and ambient occlusion tends to give good results.
- SpecTeam - Units use a normal mapped shader, which also takes into account specular, reflectivity, and glow. The team colour is also added in this texture.
- R - Reflection - makes the texture more shiny, reflecting the sky. Glossiness (inverse of roughness) from a PBR workflow gives good results.
- G - Specular - makes the texture change colour according to its environment. If you use/can convert a specular/reflectivity channel from a metalness, this should give good results.
- B - Brightness - adds bloom to the texture, taking the colour from the base colour. Specific effect depends on the type of shader used.
- A - Team colour - overrides the base colour with the colour of the units army.
- NormalsTS - the game uses a non standard set up for normals. There are only two channels, X and Y. Z is calculated during runtime and is not needed. It is very important to get the orientation right, and can be very confusing when converting normal maps for use by Supcom.
- RGB - Y - White = UP - This is a greyscale input. All the rgb channels should be the same.
- A - X - White = LEFT - This is the alpha channel
- Furthermore, there appears to be a need to have the channels at different brightnesses. The RBG channel flat value is #080808, while to achieve a flat value on the alpha channel a value of #949494 is better. The conversion factor between them is 0.79 or 1.27 (for use with the levels adjustment)