Green Rascal Design

 
 
I went over render setup with most of the students previously, but everyone needs a little refresher, it seems. If you haven't spent a lot of time messing around with different settings it can be really hard to remember what everything does and all the different places to go to change things. So here are a few basic areas to pay attention to. We'll start with the Common tab, and right now we're using Mental Ray.
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Output Size
Pay attention to your Output Size. If you're going to plot out your renderings at a large size this can make or break you. 640 by 480 is great for testing things out, and it's what I've been using for these tutorials, but it would look terrible printed at 11x17. The resulting image size, photoshop tells me, is about 14" by 23" but the resolution is only 72ppi. For presentations I'd much rather have 300ppi. Over the web it would be hard to show the difference, but it's huge. So I always bump the Output Size up to at least 800 by 600. Actually, in the past I've done my screen resolution (1200x2400) but that's because I was working on my own computer or sending my files to the render farm. In the computer lab, where space and time matter, this isn't a nice thing to do to your peers.

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Options
Now briefly look at the Options. What I do here is make sure Force 2 Sided is checked on. Here is the catch-all for surfaces with backwards normals that might appear invisible in renderings. Sometimes bad things still happen when I have this checked, but it does help a lot to have it on.

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Advanced Lighting
Moving on to Advanced Lighting... These two little check boxes can save you some time or make things look more or less realistic. Advanced Lighting is good in my opinion. I always have Use Advanced Lighting on. To save memory in my computer I like to check Compute Advanced Lighting when Required. This means it will process the scene when you tell it to render, not every time you make a change.

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Global Tuning
In the Renderer tab, check out Global Tuning. I don't usually mess with these settings, but you might want to know how to make shadows more precise or softer. These are set to .5 by default on my system, and it's a good setting. Making the multipliers 1 will add time to your rendering, but they will be more precise if that's what you want.

I don't usually mess with other settings in the Renderer tab.

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Final Gather Basic
In the Indirect Illumination tab, Final Gather is very important. I always want to check Enable Final Gather. I leave the multiplier at 1. For drafts I put the slider that says Presets to the left, or low. For final renderings I use high or very high. For most things I don't bother touching any of the other controls except Diffuse Bounces. Default it 0, I believe. I always set it at 1. Higher numbers like 2 or 3 will make the light bounce around in the model more, and it will soften the rendering. If you're having a problem with things being too crisp, try 1 or 2 Diffuse Bounces.

Advanced Final Gather options such as noise filtering can be adjusted if there is a lot of noise or speckles in your renderings. I usually don't mess with these things.

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Caustics and Global Illumination
Caustics and Global Illumination are extras that I don't usually use either. They can add more reality to your rendering, but they also can add time and processing power. Also, Global Illumination is seen as a way of cheating by some fanatics because it lightens up your scene artificially. If you are doing accurate light studies this isn't for you. That said, it can't hurt to try them out someday when you're bored. There is plenty to read in the help file about them, too.

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Processing
The Processing tab is all about files and memory. Sometimes I check the box by Conserve Memory. The following stuff I don't bother with. Geometry Caching you can read about. I think it improves performance. If your file is crashing a lot it might be worth it to check this box. That's the only thing that I think might be useful to the class at this time.

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Render Elements
The Render Elements Tab allows you to add atmospheric effects and other fancy things. I'm sorry we haven't had time to go over these things this semester, but it seems like nobody is really in need of them at this point. I usually don't use them anyway.

If you are not using Mental Ray your tabs look different! Remember if you switch renderers under the Common tab that the tabs all change and rearrange themselves. Here's what is different.
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Radiosity
Now there is an Advanced Lighting tab. Here I have Radiosity selected in the drop down. The other option, Light Tracer is good for some exterior renderings, as I've said, but most people don't use it for much. Radiosity seems to be the preferred way to go these days. Years ago this was not the case, but you can read all about it elsewhere.

Radiosity Processing Parameters provides a few buttons that allow you to reset your radiosity solution. If you make a change to some lights, you can hit Update & Start to see the new lighting solution. The progress bar is there to show you the calculation time.

Under Process you can turn up Initial Quality. Default is 85%. Sometimes I turn it up to 90% or 95%. This makes renderings take longer, but they look better. Check the box that says Update Data When Required on Start. This will help a little with memory.

The Interactive Tools allow you to brighten things up a bit by bumping up Indirect Light, or soften things a smidge with Direct Light Filtering. I rarely use these things. The Logarithmic Exposure Control Setup button takes you to the Environment box. I like to check Display Radiosity in Viewport, as I've said. But it only shows in viewports that are set to wireframe, as you can see.

Radiosity Meshing Parameters I have talked about. Enable Global Subdivision, and you can control the size of the mesh here. This effects the smoothness of light hitting and reflecting off surfaces.

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Rendering Parameters
Rendering Parameters are important. Here is where you tell Max to Render Direct Illumination and Regather Indirect Illumination. I don't usually change the number of rays or size of the radius. Sometimes I do check the box by Adaptive Sampling. This changes the density of shadows, and you can change the spacing of samples here. Sometimes I change the Initial Sample Spacing to 8x8, but this adds time. You can play with this sometime.

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Raytracer
Finally, I don't usually touch the Raytracer tab. Global Ray Antialiaser can help blotchiness. Everything under Global Raytrace Engine Options comes enabled by default, and I haven't found many reasons to change them. Show Progress Dialog helps if you need to know what's going on. It's all pretty basic.

I'm gone over all the sections I think my class needs to pay attention to at this point. Hopefully these notes spark memories of stuff we talked about in class!
 
 
Today I'm going to put up an example of the photoshop I was talking about on Tuesday just for fun. The four following images are from one camera.
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radiosity, lights high
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mental ray simple, lights high
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radiosity, dimmed lights
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mental ray, 3 light bounces, final gather, mr physical sky on...
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I started out by putting all 4 images into one file. Then I moved the last one to the top layer because I want to make sure the physical sky shows in the final version. This image shows the bottom layer as normal and the mental ray layer above it set to luminosity to brighten it up.

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Then I turned the radiosity layer above that on, and to smooth out the table I set it to divide and turned down the opacity to 50%. This made a very slight smoothing difference in appearance.

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Then I used the last mental ray rendering with that sky background on multiply to make it less bright and add some depth with an opacity of 50% to not make it too soft.

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So there is the comparison. On the left is the best quick rendering that 3ds Max gave me in under two hours. On the right is a combination of renderings I made in photoshop that brings out the best in each one. This is really really fast and simple, and I know it still looks a little fake, but it's an example of how you can take some less than perfect renderings from Max and make a much better one with very little trouble. A little light erasing here and blurring there, and you're right as rain. See, no reason to get upset if things aren't perfect the first time. After all, rendering is really an art and you can't expect your modeler program to do it all for you.

That's all I can fit in on this today. Send questions or complaints if you like.