Thursday, 16 December 2010

Bump Mapping

This is another series of tests which are a little off topic to what I've been doing previous, but also they're completely relevant at the same time. I was experimenting with Bump Mapping in Maya, Bump Mapping is a surface shader which doesn't alter the geometry but gives the impression that the object has bumps and depth to it by taking the white and black values of the image you're using as the shader and then altering the height and depth of the protusions by the light being used in the scene. So you could have a flat plane with a bump map applied to it and it will look like it has bumps and texture in the geometry, but the geometry itself will remain unaltered and flat like it was when you first made it. Through my research however I did find that there is a process similar to this one called Displacement Mapping which does alter the geometry.

I started practicing with Bump Maps on a File from my second year, it's a broken old fountain which I made for my groups Digital Environments project. The image above shows the scene file before I started practicing on it, as you can see the textures themselves look rather flat and unrealistic.

This image shows the same fountain after I applied a Fractal Bump Map to the texture on the fountain base. You can see that there is slightly more depth to the shadows, however the Fractal Map I used isn't really the best one for the type of texture the fountain is supposed to be, but adjusting the maps attributes properly should allow for some effective results, but generally using the pre loaded Bump Maps in Maya will produce mediocre results so it would be best to use my own textures for it instead.

The image above shows my first attempt at using images as bump maps rather than the pre-loaded ones already in Maya. I set up the scene using nothing more than a sphere and a plane, I then applied a sack texture as the bump map for the sphere and a wooden plank texture as the bump map for the plane. Now the sphere and the plane look like they are actually made from real materials rather than just having flat textures applied to them.

The above image shows the scene file in Maya, I have hardware texturing and High Quality Rendering turned on so I can see how the scene will look without having to keep rendering it, tis is useful as I found that adding bump maps increases the render time quite a bit and this is only for 2 basic polygon objects. I added a couple more planes to build a little set so I could do some more experimenting.

This is a render of how the scene looks when rendered.

What I wanted to try now was to see how placing a light in the scene would work with the Bump Maps. I used a directional light and loosely placed it just so I could get a shadow from the sphere against the ground plane and the wall behind it. I'm not at all proficient when it comes to using lights and everything I do has no method behind it, all i know is the type of effect i want to create and I reach that by nothing more than repeated trial and error. In the image above the shadow is too dark and bold, I wanted something a bit softer and more subtle rather than bold and in your face. 

The 3 images above are renders which show further experimenting with the shadows, light and colour. What i've found from doing this is that Bump Maps are definitely useful for objects which are not being seen close up to the camera, so objects in and around the environment in the background would benefit the most from this process because up close it can look very messy. Also after doing this I've found that it may not be necessary to use this method at all just because of the style we're going for which is a more simple and stylised look rather than a realistic detailed look.

One problem I found whilst using my own textures as bump maps was that once I had applied it to the object and closed the attribute editor for the shader it was impossible for me to find the editor at a later time to adjust the attributes of my textures, I searched in the outliner for it as well as through all my material tabs but couldn't find it anywhere, it has to be in there somewhere but I just can't find it at the moment. the problem this is now causing for me is that I have to make sure i have the attributes set exactly how I want them before I close it which is annoying because I will constantly be adjusting the settings to get the best outcome.

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