Author Topic: Bucket Size  (Read 791 times)

Offline dorianvan

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Bucket Size
« on: May 26, 2017, 12:35:27 AM »
Does anyone know how bucket size effects rendering? Is there an ideal size and how do you know? Thanks.
-Dorian

Offline Oshyan

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Re: Bucket Size
« Reply #1 on: May 26, 2017, 04:34:31 AM »
Changing it can have an effect in some scenes, but generally the defaults are best, just like the Subdiv Cache. It is set automatically for a reason. If you're looking for ways to optimize render time, generally it's best to look elsewhere.

And in case you're wondering and decide to test yourself, sometimes reducing to 128x128 buckets can be a bit faster. Going much smaller than that is usually *slower*. Larger is also usually slower.

- Oshyan

Offline bobbystahr

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Re: Bucket Size
« Reply #2 on: May 26, 2017, 12:30:13 PM »
Good info, always meant to ask about that but brain cramped it...Thanks Oshyan.
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Offline Matt

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Re: Bucket Size
« Reply #3 on: May 26, 2017, 05:20:10 PM »
There are some circumstances where I might change the defaults, but they are rare. If there is a very slow-to-render portion of the image and it's a small area compared to the rest of the image, sometimes reducing the bucket size can help. In extreme cases I have gone as low as 50x50. But it is quite rare to need to do this. On most scenes this would make the render slower.

Bear in mind that the number you enter is not the actual bucket size. When "allow auto reduction" is enabled it's just a maximum. It's forcing Terragen to always make sure the buckets are never larger than that number. The default is 256x256, but the renderer usually produces smaller buckets than that, especially with high-thread renders. Therefore if you change it to 128x128 it might operate the same as 256x256, but it depends on number of threads, resolution and AA.

Matt
« Last Edit: May 26, 2017, 05:21:50 PM by Matt »
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Offline Matt

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Re: Bucket Size
« Reply #4 on: May 26, 2017, 05:26:12 PM »
But as Oshyan says, generally the defaults are usually fairly optimal. It automatically adjusts to resolution, thread count and AA. Only change the defaults if you are prepared to run tests to verify render times in each scene, and don't save the changes into your default project.

Matt
Just because milk is white doesn't mean that clouds are made of milk.

Offline dorianvan

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Re: Bucket Size
« Reply #5 on: May 26, 2017, 07:10:38 PM »
Thanks. I just wanted to understand when it's in my best interest to change it.  I'll leave them at default unless I'm exporting terrain and don't want the overlapping polys.
-Dorian

Offline Oshyan

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Re: Bucket Size
« Reply #6 on: May 29, 2017, 09:45:58 PM »
For future readers, I also want to note that I have tested smaller bucket sizes in several cases where I expected it to speed things up due to a single bucket taking a disproportionately long time to render for larger bucket sizes. However what often happens in these cases is that it's just a smaller bucket that ends up still sitting there on one or two threads for a long time. It does sometimes reduce quite how long that is, but it doesn't have the significant affect one might hope because that small area of the scene is still just disproportionately hard to render and we're not able to intelligently distribute the render load totally evenly across available cores.

- Oshyan

Offline Matt

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Re: Bucket Size
« Reply #7 on: May 30, 2017, 07:40:00 PM »
That's good to know, Oshyan.
Just because milk is white doesn't mean that clouds are made of milk.