|
Creating a great looking gun for a video game is a complicated process. Gone are the days where you would create the mesh and slap on a texture. Now there are many steps to go through before the weapon ever makes it in to the engine for testing, and if you want to make something amazing, a great deal of care must be put in to every step of the process.
I will chronicle the steps I used to create a sci-fi gun. This is not a tutorial but could be used to get an idea of workflow. |
Sci Fi Gun 3ds Max
|
High Poly Mesh
The first step in modeling our game ready weapon is to create a high poly version. We will use this to bake normals and possibly other things like occlusion and height to a low poly (real time ready) version of the gun.
This step is incredibly important. Most steps are important, but the high poly version should represent the shape of the weapon precisely. Some details can be added later, but keep working at it until you are satisfied. Don't intend to fix things later down the line.
For this step I used 3ds Max. This is what I'm most familiar with, and I like to do as much as possible in this one program. What I did was use NURMS to subdivide and smooth out the mesh. This takes a good amount of practice, and if you are just starting out, I'd suggest playing around with different edge loops and bevels to get a feel for how NURMS subdivide.
While there are those that say working with edge loops and quads isn't important in this stage, I disagree. Be precise, and use good modeling practices, even in this stage. In order to match my low poly mesh as close as possible to the high I will base my low poly mesh on Stage 1 of the Nurms, so I need good loops and quads.
Below is the viewport render of the high poly version of the sci-fi gun. It is built in different pieces, so that baking will be easier later on. I made an effort to not take the easy way out with anything, keeping things sharp and very curvy.
This step is incredibly important. Most steps are important, but the high poly version should represent the shape of the weapon precisely. Some details can be added later, but keep working at it until you are satisfied. Don't intend to fix things later down the line.
For this step I used 3ds Max. This is what I'm most familiar with, and I like to do as much as possible in this one program. What I did was use NURMS to subdivide and smooth out the mesh. This takes a good amount of practice, and if you are just starting out, I'd suggest playing around with different edge loops and bevels to get a feel for how NURMS subdivide.
While there are those that say working with edge loops and quads isn't important in this stage, I disagree. Be precise, and use good modeling practices, even in this stage. In order to match my low poly mesh as close as possible to the high I will base my low poly mesh on Stage 1 of the Nurms, so I need good loops and quads.
Below is the viewport render of the high poly version of the sci-fi gun. It is built in different pieces, so that baking will be easier later on. I made an effort to not take the easy way out with anything, keeping things sharp and very curvy.
Low Poly Mesh
With the high poly mesh of the gun complete, I will now turn attention to the low poly version. I will bake the surface normals of the high poly mesh on to the low to create the final shape of the gun. There are many ways to create the low poly version, and all of them are time consuming if you want to get things right. Some people prefer to create the low poly version from scratch, and in many cases this is a good way to go, but for this case the high poly mesh was made with the idea that it would be reduced later. Planning ahead is important.
Here is the high poly version version of one part of the mesh. This is NURMS with 4 iterations and is far too polygon heavy at over 400,000 triangles.
Here is the high poly version version of one part of the mesh. This is NURMS with 4 iterations and is far too polygon heavy at over 400,000 triangles.
Here is the same piece at NURMS with 1 iteration. Using this stage as a starting point for our low poly mesh insures that the curvatures match up nearly perfectly to the high poly mesh. The shape is defined mostly with NURMS 1 and refined when adding more iterations, so this is a great starting point to get a good silhouette. 6,000 polygons is still too high, but I can knock that down a bit.
At this point I remove edge loops where they are unnecessary, and I weld vertices together. My goal here is to keep with good modeling techniques, and I pay special attention to how polygons are lit. In the end the normal map will do most of the work in terms of how the model is lit, but bad lighting transitions of the low polygon mesh can still cause problems
Here is the result.
Here is the result.
This leaves a with 2,500 triangles for the part, which is what I budgeted for. This will be the final version for this piece.
For the remainder of the gun pieces I will reduce the number of polygons in a similar way.
For the remainder of the gun pieces I will reduce the number of polygons in a similar way.
UVs and Baking
Once you have a high and low polygon version of each piece of your gun now it is time to bake the detail from the high polygon mesh onto a normal map texture which will be applied to the low poly mesh. The combination of the low poly mesh and the normal map with the help of shaders will create the illusion that the pieces are much more detailed than they are.
So, the low ploy mesh needs to have its UVs laid out. I suggest unwrapping each piece, baking the normal map, and then testing the results in the engine of your choice one piece at a time. Combining and packing all the UV islands from all the pieces can be done later. Doing it this way means you will have to bake again, but I like getting things into the engine to test as quickly as possible. At this point I export an FBX of the piece so I can get it into Unreal easily.
For baking I use 3ds Max's Render to Texture feature. Make sure both models are at the same position (overlap). I bake a local space normal map. I like to use 3ds Max for baking because there are a good deal of anti-aliasing and supersampling options that I can use if the bakes turn out to be too jagged. There many other ways to bake, but this workflow works for me and yields great results.
Here is the test bake of the local space normal map for the piece shown above. This came directly from 3ds Max. You can see I didn't pack the UVs efficiently yet since this is just to test the bake results quickly in engine.
So, the low ploy mesh needs to have its UVs laid out. I suggest unwrapping each piece, baking the normal map, and then testing the results in the engine of your choice one piece at a time. Combining and packing all the UV islands from all the pieces can be done later. Doing it this way means you will have to bake again, but I like getting things into the engine to test as quickly as possible. At this point I export an FBX of the piece so I can get it into Unreal easily.
For baking I use 3ds Max's Render to Texture feature. Make sure both models are at the same position (overlap). I bake a local space normal map. I like to use 3ds Max for baking because there are a good deal of anti-aliasing and supersampling options that I can use if the bakes turn out to be too jagged. There many other ways to bake, but this workflow works for me and yields great results.
Here is the test bake of the local space normal map for the piece shown above. This came directly from 3ds Max. You can see I didn't pack the UVs efficiently yet since this is just to test the bake results quickly in engine.
I then open Hardplane and input the local space normal map baked from MAX along with the FBX of low polygon model. Target Engine is set to Input Tangent and Binormal. Hardplane will use the information to create a tangent space normal map that we can apply to the model with a material in Unreal Engine.
