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Fine tuning your Global Illumination settings is a important part for optimizing your finish renders. And in this case, I'm going to go here, select my render node. And then, I'm also going to go in here to my can material and I'm going to turn on my basic material up over the top. And that's going to allow me to get a clearer view of just the lighting quality and, and can see what's going on here, without having it encumbered by all of the different things with the texture. Now, that said, you can have a little bit of roughness in the lighting quality. And when applied over a more complex texture, you might not notice. But it's usually a good rule of thumb to get things as clean as you can within reason, and within a good render time.
And then, add your textures back in because you don't want to have some modeled lighting mess up your textures. But that's going to be harder to read if you have everything turned on. So, for that case, I'm going to go ahead and turn that back on here. And (SOUND) I'm going to over to my Global Illumination settings. And, then, let's just open this up, so we can see. Now, I have a pretty basic set of, settings turned on here. These are not default but they are the ones that I use for a lot of other things. My Irradiance Rays are set to 128. That's relatively low but it's going to keep a good relatively quick rate rays.
My Irradiance Rate and Ratio are set to 5 and 3, respectively. And then, the Interpolation Value up to 8. Now that's going to go together to give a good relatively smooth overlook that might lack a little bit in some of the details. But overall should give a good balance between speed and quality. Now the other thing to note is that I have Indirect Bounces set to 2. Sometimes that Indirect Bounces setting can cause a real slowdown in rendering. Although, often times I've noticed that keeping it between 1 and 2 is a relatively minor difference. But, one thing is, if we turn it down to 1, it's going to refresh a little bit more quickly on here.
And without the extra bounce of light coming off of the floor in the background, sometimes it's a little bit easier to see how the lighting is going to affect the surface. In the case of these cans, you can see that we're getting a really kind of rough overall look here. So in this case, this would be where you want to increase your Irradiance Rays. This is going to be the place that's going to allow you to get something a little bit cleaner. So, I'm going to go up to 256, and then I'm just going to use the paint to preview and I'm just going to Mouse over kind of this middle section here, and see that we got that a lot of those splotches going away.
And I could go even higher just based off of render time, the choice will be yours. But if you have a much faster machine than me, this is just a relatively middle of the line quad core. Then you can go a lot higher in your finished renderings. So I think it's set at 512. It's getting pretty smooth over all. And then, when I turn that second bounce back on, it's going to clarify a lot of the lighting here. This should look pretty good. Yeah, so that's pretty nice and clean through here. And I'm just again, going to kind of mouse over this middle section. Now alternatively if you want to really check these settings without having to worry too much about the entire thing rendering.
You can turn on the render region tool which gives you kind of an interactive way to decide where you want your image render. So, I'm just going to drag out kind of this middle section of this can here and now you can see only that section is going to render. So I can make this, render preview maximized and now you can see it's only going to deal with, what's directly inside of that little square. And this is going to let this, kind of, refine itself much more quickly because it's not worrying about, the other stuff outside of the scene.
And overall, I'd say this is looking pretty good. You will notice that we're getting a little bit of kind of (INAUDIBLE) reflections where the light is focusing off of the drops. And that's going to cause a little bit of the modeled appearance, and that's okay. That's the kind of realistic thing that we would be expecting. But it's where we see relatively smooth not patchy coloration across. That's going to be. Where we'd want to go. So, for this case, I'd say that a render setting with a radiance rays of about 512 is going to give me the best thing for the best thing for the buck.
Again, you can always go higher but you're going to really sacrifice your render time. So that's going to help me get that there. Another thing to keep an eye on is the indirect caustics. Now if you don't want those caustic reflections here I'm going to turn this down to none. And you'll actually see that this is going to get much, much darker. And that's because we're not getting the light focusing underneath these. Instead, all we're getting is the shadows off of these, so something to be careful of when you can turn it off, sometimes it will save you some render time.
You can see this is clarifying more quickly, but at great expense to the image quality. So, I'm going to set this over to refraction only. And this should give us a decent mix. It was set to both, which means that wherever light is hitting a bright, reflexive surface, then that surface is going to cause a little bit of a, kind of, bounced focus reflection of light. In this case, we would see it here at the top side of this water drop here, but it's not present. If I turn it to reflection only, the shadow under that might overpower it so you won't see it, but if we change it to both, there we go. Now you'll see that we won't have a dark spot here but it gets a little bit lightened up by the reflection off of this drop there and then on the lower side of it.
You get the light passing through, and so you get the indirect cause that's kind of giving you this little bit of reflection over there. If you happen to be doing a scene that mixes using CG light, like directional lights and spotlights with your Global Illumination, then you might want to consider turning on the Direct Caustics. And these you get a little bit more control over the actual render settings. The total number of photons that are in there and then the local photons, and remember, that just like anything else higher photons, which is equivalent to higher arrays is going to give you higher render times as your total photons. But its going to give you better quality more focused more realistic looking caustics.
A lot of times with the scenes that we've been doing we've just been looking at only using Global Illumination. But if you happen to be using some direct illumination that's where this direct caustics will come in. And you can also cache those will walk through mode just like you can cache your overall lighting with walk through mode. And, if you're going to be using an animation, the only thing that has to be recalculated for subsequent frames is whatever is in view, in camera view that is, that wasn't in the camera view for the previous frame. So that saves a lot of time with those irradiance caches. When you're rendering out your finished renders of any animation. So if you're going to move the camera around, if you're going to rotate the cans or something like that, then definitely want to consider turning on Walkthrough Mode.
Especially if the objects are going to be changing positions drastically, it's mostly positions in camera like a walkthrough. That's why they call it Walkthrough Mode. Then this will definitely help increase the cache speed of your finished frames and it's going to speed you up. The first frame will still render at the regular speed but every subsequent frame will be significantly faster. So, optimizing those settings is going to help you to get the best balance of quality versus speed. Adjust them to where you need them to your finished project to get the best quality with the amount of time you have.
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