Thursday, 5 December 2013

Vehicle Project : Part 2

After finalising my vehicle model I moved onto making the environment. The tri limit for the vehicle was 10,000. But when modelling it I tried to make every triangle count and not needlessly put in more edge loops just because I have more triangles in my budget to play with. This is why I have only used 4,068 tris. I believe adding anything more will not change the silhouette and I would be adding loops for the sake of it

My plan for the environment was a small repair garage/pit stop. The aim for the environment was to keep it simple as to not distract the viewer from the vehicle. The plan for the environment was to have one strong light source. This was in the form of several bright strip lights directly above the vehicle.

For some of the more detailed environment assets I made a highpoly for them to bake down from. These assets where the shutters and the toolbox. The shutters were made very quickly as all I had to do was make one ‘link’ which is made up of chamfered boxes which are then duplicated to create a wall of these links to create the shutters. Below shows the highpoly assets:

Highpoly shutters

The environment was then modelled and textured. The budgets for the environment was 10,000 tris and 1 1024 D/N/S. The scene came to 3, 068 tris as I didn’t need any more. The texture budget was split up into 2 512s for the tiling textures and 2 512s for the unique assets.

Next stage was unwrapping the vehicle. Unwrapping was an easy process, some parts of the model I mirrored to save on texture space, but the more visible parts I didn’t mirror as I want asymmetrical detail across these parts.

Different texel density. More UV space for more visible parts 

Texturing was a simple process. But to create realistic layers of damage I textured the vehicle in a way that a real vehicle is painted.  Like this: base metal > redpaint > whitepaint > decals. This allowed me to mask off individual layers to reveal the layer beneath, creating believable damage/scratches.

I also looked into metal discolouration for the jet engine exhaust. This simple effect of adding a few different colours adds a lot of character to the model.

Diffuse Map

The brief asked us to produce a lightmap for the environment as the shader we were given was limited in the number of lights in the scene and lack dynamic shadows.  I made this by setting up lights in the environment where the actually light models were, rendered out a lightmap which I then applied to the second channel of the environment. This gave me a nice and accurate baked shadow of the vehicle on the floor.

Setting up lights for baking the lightmap

We also had to produce a cubemap for this project. It was one of the most important parts of this project as this technique produces realistic reflections of the local environment on the model.
It was a simple process as well. I set up 6 cameras, facing 6 different directions and placed them where the vehicle will be. From this I took a screenshot from each camera and stitched them together in Photoshop in a certain order.

Setting up cameras for cubemap

Cubemap result

Along with the cubmap we had to create fake HDR. This was done by painting what parts of the cubemap you want visible in the alpha channel. The way I did this was merging all the layers and changing it into greyscale, then tweaking it through curves. Doing this made my lights a bit darker, so I repainted them pure white to get the strongest highlights I could when using the shaders.


After this was all done I could start tweaking all the parameters in the shader to get the most accurate material properties I could.  After I was happy with the results I figured some parts of the model didn’t reflect  the model just came from a race – it still had that highpoly polished surface look. I looked at my spec map and realised that it was too white/little contrast, which gives very little surface variation. I solved this by overlaying a few different photo textures over the body. This small change gave a real nice surface variation, almost like loads of dirt being kicked up settling on the vehicle.

Before and after tweaks to the spec map

Below are the final renders within 3dsmax’s viewport using codemastsers car shader:

Overall I feel like this project came out ok. A lot of decisions i made turned out to be the wrong decisions. I feel like this is the first project in a very long time where im not happy with the results and given a chance I would completely redo the project. 

I think the first major mistake I made was to abandon my original idea of the Caterpillar 797F Dump truck which I had in my head for at least 2 months prior to the project starting. I dropped this decision because the project brief has a great focus on materials and I thought the dump truck didn’t have enough varying materials to show off the Codemaster shaders. So I decided to concept my own vehicle with different material properties.   
I think the vehicle came out relatively well, different material properties can be recognised. But I think the environment and lighting brings down the overall quality of the scene. The lighting within the scene is rather flat, making the environment look very amateurish. My environment idea was to have one bright light source coming from the ceiling which is how actual pit stops look. But this made everything overly bright and washed out. In hindsight I should have had another light source within the scene with some colour from it. Possibly have the shutters open so the sun would be another source of light, this would also give more interesting reflections on the vehicle as well as produce a more interesting light map. 

I think this project has been a major learning experience for me. Learning to use shaders used by actual game studios and all the little tricks they used to fake certain techniques has been great. I will take everything ive learnt from this project and apply to all my future projects. 

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