Reflections Part three

This tutorial covers using reflection maps for reflections. In this tutorial we'll be making a simple fast rendering of a car that has a "faked" reflection.

What Are Reflection Maps

Reflection maps normally find a home in video games. What a reflection map does is allow an object to have a reflection of an image (this image would be a panoramic image). This means that instead of only getting reflections from objects in the scene, it's also getting panoramic image (the reflection map). The plus sides of using reflection maps in Maya are; faster rendering, a realistic environment, and faster render.

Getting Ready

First you'll need a panoramic image for the reflection map. A good way to find one is Google (I supply a free one here). Since we'll be using Maya Software as our renderer, we won't be able to use Mental Ray's paint shader. Because of that we'll have to create own own paint "texture".

Creating A Paint Texture

For this you'll need Adobe Photoshop.

Step one - Create a new file (go to file>new...). Set the width and height to 512 px.

Step two - Fill the entire background layer the color that you want your paint.

Step three - Go to filter>noise>add noise... Set the amount to 2.0, set the distribution to uniform and make sure Monochromatic is checked. Hit OK.

Step four - We're going to add noise again. Go to filter>noise>add noise... Set the amount to 4.8 this time and un-check Monochromatic.

Step five - Okay, now go to file>save. Set the format to .BMP. Name it something like Car_paint and save it someplace on your hard-drive.

If you do not have Adobe Photoshop, you can just use the texture below as your car paint.

In this tutorial we'll be using a car body I modeled. You can download the car body below (un-zip the file and copy the models into the scenes folder (C:\Documents and Settings\Your name here\My Documents\maya\projects\default\scenes) and the textures into thesourceimage folder). Open Maya and open the scene car_body.ma. This has the simple car body in it. Set the menu set to rendering and the shelf to rendering.

Creating The Shader

Step one - In the Maya scene, select the car body. And on the rendering shelf create a blinn shader. Open the attributes editor (window>attributes editor).

Step two - Next to the attribute color, click the checker board. A window called create render node will come up. You'll want to click the icon next to the word file. This'll create a render node that we can assign a texture. In this case it'll be our car paint texture. The attributes editor will change and show the files attributes. Click the folder icon adjacent to the text image name. Locate where you saved the car paint texture and hit open.

Step three - Still in the attributes editor, find the tab on top of the attributes editor, place2DTexture1. Roll down its attributes and find the attribute Repeat UV. Set both fields to 10. This will make it tile across the car body.

Step four - Select the car or, if it's already selected, hit the checkered wave icon on the rendering shelf.

This'll take you back to the blinn shader attributes. Roll down the attributes and set the Eccentricity to 0.3. Set the specular roll off to 1.0. Set the specular color to white. Set the reflectivity to 0.3.

Setting Up The Reflection Map

This is the main part of the tutorial. What we're going to do is create an environment map and then assign it to the blinn.

Step one - With the attributes editor still open to the blinn attributes, (if not select the model and hit the wavey checkerboard on the rendering shelf) in the attributes editor find the attribute reflected color. Click the square checker board beside it and the create render node window will open up. Roll down the create render node window and find environment textures. We're going to create an Env Sphere. Click the icon to create it.

Step two - The attributes editor will change and show the Env sphere attributes. Click the checker board adjacent to the text "image". We're going to create another file render node. Click the file icon from last time. Click the folder icon adjacent to the text image name. Browse and find your panoramic image. Click open.

And there you have it; the panoramic image has been assigned as an environment map. Follow these next steps to show how to be able to view the reflection on the car in the view port.(the way the car looks in the view port does not necessarily show how it'lll look rendered).

Step one - On the view port menu, go to shading>hardware texturing. Or hit 6 on the keyboard.

Step two - On the view port menu go to rendering>high quality rendering (some graphics cards may not support this). Now you'll be able to see the reflections in the view port.

Conclusion

This is the last of the three part series on reflections. You can view the other two at thses links;

http://www.3dtutorialzone.com/reflections-part-two/

http://www.3dtutorialzone.com/reflections-part-one/