This article will try to explain the steps needed to create an asset for StarCraft2 from start to finish.
I will try to keep is updated as much as I can.
Things you should know before reading this article:
The article assumes you already know how to model both high and lowpoly meshes
The article is based on trial and error, and the information provided should not be treated as a fact
This article may become outdated, but some of the techniques described will likely still be applicable
The article contains subjective views
May contain nuts
Table of Contents:
Planning your asset
Modelling the highpoly mesh
Modelling the lowpoly mesh
Tweaking the lowpoly mesh
Baking normals
Texturing
Modifying the StarCraft2 shader
Exporting
Importing into StarCraft2
1. Planning your asset
When producing an asset with the intent of using it in StarCraft 2 one should keep in mind the scale of the
existing ingame objects, the camera distance, field of view, angle of attach, etc.
Unless the map for which the asset is intended will be using camera model(s) completely different from the original,
you will need to take a few things into consideration before starting work on the asset.
The following assumes that the intended map will use a default(or close to) camera:
The camera has a very high angle of attack(pitch), high distance from the target, and a relatively large field of view. This means that your asset will, mostly, be viewed from above, and will be relatively small.
Adding excessive details to the bottom of the asset would be redundant, and would cause unnecessary loads
on the game engine.
The asset itself should have a higher concentration of details on the top, while the bottom has the minimum
details needed to convey the feeling intended.
You need to consider the silhouette definition very well, as in an RTS game it is likely that there will be a high concentration of assets in a very small area.
Having a clear, readable silhouette and color scheme is key. I urge the readers to avoid glowy bit hell if the asset has bad readability.
That's never helped anything.(see UT3 etc.)
When picking colors for your asset, try to avoid using excessive black or grey, unless necessary, as these colors are very common across all SC2 assets
and may greatly decrease the asset's readability ingame.
2. Modelling the highpoly mesh
When modelling the highpoly you should always keep in mind the scale of the asset.
If you're adding fine details, they will likely look tiny ingame, if they're visible at all.
On the highpoly, you should keep the scale of the details fairly large. They should be clearly visible even if the camera is
far from the model. As with any model, try to avoid concave polygons, and stars. In some cases, pentagons may work very well with corner
joints.
3. Modelling the lowpoly mesh
Because of the scale of the model, and camera distance, you can afford to omit some of the larger details from the lowpoly model.
Normal maps should work fairly well at a distance. Try to keep the model in quads(We'll discuss triangulation later), as it makes
the model easier to manage.
A thing to keep in mind is that ngons and stars are VERY bad. Avoid them at all costs. Keep the topology in triangles and quads.
Concave polygons also seem to cause some trouble, but not as much.
4. Tweaking the lowpoly mesh
What you should do is manually check your triangulation, so that you don't have stars in the mesh. After that, set your normals
as you would for baking. The tricky part is that you need to split your model by smoothing groups(this may be done after baking as well, with no adverse side-effects).
Otherwise, when the model gets exported, one smoothing group gets applied to the whole model. This potentially causes the normals to break,
and some serious specularity issues(depending on the model).
Depending on your model, you may need to explode it for baking.
5. Baking normals
There are no special steps for baking.
I strongly advise AGAINST using 3ds Max's baking engine(or any other app's for that matter).
The built-in baking engines are mostly horrible.
I urge people to use xNormal for baking. It's a free program that can bake AO, normals and some other stuff with very high
quality output.
You don't need to make a projection cage, and you can set ray distances.
You can download xNormal here: http://www.xnormal.net/
I suggest baking AO and then setting the result as overlay with a medium opacity over your diffuse map,
as it gives the model some extra depth.
6. Texturing
Diffuse
When creating the diffuse map, do it as you would normally. Try to use multiple layers for each element, as this may come in handy later.
If you want to use team colors, you need to add an alpha channel.
On the alpha channel, white is your original texture, and black is where the team color will appear.
This is where multiple layers come in handy.
You can select sub-elements that you want to retain their color and fill the selection with white(or whatever) on the alpha channel.
Specular
The specular map is a bit weird. The color has a huge effect on the model, and the luminosity has a huge impact on the specularity, regardless of what settings you use in the shader itself.
Try to keep the specular desaturated, highly contrasted and very bright. You don't need an alpha channel for this map, but in case it looks off
try adding a pure white alpha.
Normal
The normal map is the most retarded of them all.
After you've finished work on your normal map, you need to do the following:
The output of the RGB should look orange. If the normal map seems strange ingame, you should try inverting the green channel and re-importing.
Emissive
If you are using an emissive map, you should keep in mind that it has a HUGE effect on the look of the model.
It's basically a self-illumination map, that starts glowing when it reaches a certain point.
You can use alpha for team color.
Save the image as DXT3, ARGB, 8 bpp, explicit alpha with NO MIP MAPS.
<sub>StarCraft2 generates its own MIP maps, and if you already have them exported, the overall quality of the image will greatly decrease.</sub>
You may wish to use different settings, but these are the ones I found work best.
First, you'll need to import an existing StarCraft2 model into your modelling package.
Once imported, move it to the side so it doesn't get in the way.
Go to an empty material slot and change the material type to the new StarCraft2 shader.
<sub><<TODO: Expand>></sub>
Specularity and HDR Specular Multiplier both control specularity.
For metallic-like specularity, I have found that 100 specularity and 1.5 HDR specular are decent values.
This may depend on your specular map as well.
The other settings should be pretty straightforward.
Refer to the image below for examples of Specularity and HDR spec values ingame:
With the shader set up, insert your maps into it.
When doing so, make sure to use StarCraft2 Bitmap.
8. Exporting
When exporting the asset, delete or hide all other models in the scene.
Uncheck export hidden and frozen objects in the exporter.
The "Initial Texture Path" is where your textures will need to be placed in the StarCraft2 editor for them to be linked to
the model. Make sure you have "Flip UV Y-coord" checked. The animation settings will not be covered, as they are outside the scope of this tutorial.
9. Importing into StarCraft2
When importing, first import the textures.
This will prevent the model from caching itself without textures. After that, save.
This will write the textures to the map and generate MIP maps.
After that, if you haven't already done so, select the textures and rightclick>move them to the directory specified during the export.
Import your model into any directory. The texture path is absolute so you don't need to worry about model location.
You should now have a working model inside StarCraft2. Congratulations!
Appendix A
Useful links:
This article will try to explain the steps needed to create an asset for StarCraft2 from start to finish. I will try to keep is updated as much as I can.
Things you should know before reading this article:
Table of Contents:
1. Planning your asset
When producing an asset with the intent of using it in StarCraft 2 one should keep in mind the scale of the existing ingame objects, the camera distance, field of view, angle of attach, etc.
Unless the map for which the asset is intended will be using camera model(s) completely different from the original, you will need to take a few things into consideration before starting work on the asset.
The following assumes that the intended map will use a default(or close to) camera:
Having a clear, readable silhouette and color scheme is key. I urge the readers to avoid glowy bit hell if the asset has bad readability. That's never helped anything.(see UT3 etc.)
When picking colors for your asset, try to avoid using excessive black or grey, unless necessary, as these colors are very common across all SC2 assets and may greatly decrease the asset's readability ingame.
2. Modelling the highpoly mesh
When modelling the highpoly you should always keep in mind the scale of the asset. If you're adding fine details, they will likely look tiny ingame, if they're visible at all.
On the highpoly, you should keep the scale of the details fairly large. They should be clearly visible even if the camera is far from the model. As with any model, try to avoid concave polygons, and stars. In some cases, pentagons may work very well with corner joints.
3. Modelling the lowpoly mesh
Because of the scale of the model, and camera distance, you can afford to omit some of the larger details from the lowpoly model. Normal maps should work fairly well at a distance. Try to keep the model in quads(We'll discuss triangulation later), as it makes the model easier to manage.
A thing to keep in mind is that ngons and stars are VERY bad. Avoid them at all costs. Keep the topology in triangles and quads. Concave polygons also seem to cause some trouble, but not as much.
4. Tweaking the lowpoly mesh
What you should do is manually check your triangulation, so that you don't have stars in the mesh. After that, set your normals as you would for baking. The tricky part is that you need to split your model by smoothing groups(this may be done after baking as well, with no adverse side-effects). Otherwise, when the model gets exported, one smoothing group gets applied to the whole model. This potentially causes the normals to break, and some serious specularity issues(depending on the model).
Depending on your model, you may need to explode it for baking.
5. Baking normals
There are no special steps for baking. I strongly advise AGAINST using 3ds Max's baking engine(or any other app's for that matter). The built-in baking engines are mostly horrible. I urge people to use xNormal for baking. It's a free program that can bake AO, normals and some other stuff with very high quality output. You don't need to make a projection cage, and you can set ray distances. You can download xNormal here: http://www.xnormal.net/
I suggest baking AO and then setting the result as overlay with a medium opacity over your diffuse map, as it gives the model some extra depth.
6. Texturing
Diffuse
When creating the diffuse map, do it as you would normally. Try to use multiple layers for each element, as this may come in handy later. If you want to use team colors, you need to add an alpha channel. On the alpha channel, white is your original texture, and black is where the team color will appear.
This is where multiple layers come in handy.
You can select sub-elements that you want to retain their color and fill the selection with white(or whatever) on the alpha channel.
Specular
The specular map is a bit weird.
The color has a huge effect on the model, and the luminosity has a huge impact on the specularity, regardless of what settings you use in the shader itself. Try to keep the specular desaturated, highly contrasted and very bright. You don't need an alpha channel for this map, but in case it looks off try adding a pure white alpha.
Normal
The normal map is the most retarded of them all.
After you've finished work on your normal map, you need to do the following:
You can use these Photoshop actions for doing the normal map
The output of the RGB should look orange.
If the normal map seems strange ingame, you should try inverting the green channel and re-importing.
Emissive
If you are using an emissive map, you should keep in mind that it has a HUGE effect on the look of the model. It's basically a self-illumination map, that starts glowing when it reaches a certain point. You can use alpha for team color.
<sub>
<<TODO: Expand for the other maps>></sub>Exporting
When exporting, use the DDS(DirectDraw Surface) format by nVidia.
You can find the plugin at http://developer.nvidia.com/object/photoshop_dds_plugins.html
Note that the plugin does not work for 64bit versions of Photoshop.
Save the image as DXT3, ARGB, 8 bpp, explicit alpha with NO MIP MAPS.
<sub>StarCraft2 generates its own MIP maps, and if you already have them exported, the overall quality of the image will greatly decrease.</sub>
You may wish to use different settings, but these are the ones I found work best.
7. Modifying the StarCraft2 shader
At the time of writing, the only way to import/export models for StarCraft2 is using NiNtoxicated's M3 plugin for 3DS Max or B<sub>(l)</sub>ender. You can download it here: http://www.sc2mapster.com/assets/m3-export-plugin-3ds-max/
First, you'll need to import an existing StarCraft2 model into your modelling package.
Once imported, move it to the side so it doesn't get in the way. Go to an empty material slot and change the material type to the new StarCraft2 shader.
<sub>
<<TODO: Expand>></sub>Specularity and HDR Specular Multiplier both control specularity. For metallic-like specularity, I have found that 100 specularity and 1.5 HDR specular are decent values. This may depend on your specular map as well. The other settings should be pretty straightforward.
Refer to the image below for examples of Specularity and HDR spec values ingame:
With the shader set up, insert your maps into it. When doing so, make sure to use StarCraft2 Bitmap.
8. Exporting
When exporting the asset, delete or hide all other models in the scene. Uncheck export hidden and frozen objects in the exporter.
The "Initial Texture Path" is where your textures will need to be placed in the StarCraft2 editor for them to be linked to the model. Make sure you have "Flip UV Y-coord" checked.
The animation settings will not be covered, as they are outside the scope of this tutorial.
9. Importing into StarCraft2
When importing, first import the textures.
This will prevent the model from caching itself without textures. After that, save.
This will write the textures to the map and generate MIP maps. After that, if you haven't already done so, select the textures and rightclick>move them to the directory specified during the export. Import your model into any directory. The texture path is absolute so you don't need to worry about model location.
You should now have a working model inside StarCraft2. Congratulations!
Special thanks to Phaos for making this happen.