A great way to significantly speed up your renders during development

[FrankB]

Hi all,

I'd like to share with you a habit I have developed for myself, that I find I'm using almost everytime nowadays.
You know the situation when you are in the process of developing an image, and you're doing test render over test render to see if your latest changes turned out ok. These endless minutes and hours just to get a decent preview of what you're doing.

I found that "ray trace everthing" (RTE) is one of my best friend, especially when the development focus is on the sky and the athmosphere in general.

Try this out: make a big fat cloud that would usually take long to render. Then, setup your render node to use RTE. Now comes the important point: set AA to 1 - yes, only 1 (for previewing that's enough in most cases). You can leave the render detail setting at whichever level you need GI to be, because GI is the only element still controled by the detail setting once RTE is enabled.

Now render away. Remember, this is a preview quality setting, but it's actually quite good with sky-focused images. Most scenes with these settings, at 600px wide, render in under a 30 seconds on a i7 920 on 8 threads, but you get a decent size preview at a reasonable time.

I hope this is helping others as much as it did help me
Frank

[Oshyan]

Actually terrain quality is still controlled by Detail with RTE, only at I believe 1/4 normal detail. That's why you get the terrain blockiness issues, which do make RTE impractical for use when there is much terrain in view.

That being said RTE is definitely very valuable if used correctly.

- Oshyan

[FrankB]

oh, yeah, right, forgot to mention that, but my point is really when you're in the process of developing the sky, and can ignore the terrain for test renders to some degree. And AA at 1 with RTE make it sooo quick.
What also works is to set detail to 2, but then ensure that GI is set very low (1/1)

[domdib]

An interesting tip Frank, thanks!

[FrankB]

you're welcome. I hope that everyone tries this out at least once. It's a major productivity boost during image development in most cases.

Frank

[PorcupineFloyd]

I wish I had more time for Terragen. Since I bought my camera and have to finish my BA I haven't done a single render I'm afraid. And I really miss those hours of re-rendering previews after changing one parameter ;-)

As for the tip: I usually also turn off soft shadows when doing preview renders. This gives dramatic speed boost. And crop like hell :-)

[FrankB]

Of course, soft shadows must be off during development. But soft shadows off is the default setting anyway, luckily

[Hannes]

Wow, Frank, thanks a lot for this tip!! The water in my "Caribbean" project takes ages to render, even with preview settings, but with your "RTE"-trick at least a crop is done in minutes! κύδος!!!!!

[Dune]

Water? Why don't you replace the water shader by a surface shader temporarily? I always do that. As well as masking the non-water out with the default shader opacity input and a mask. By the way; speaking of soft shadows; if your terrain is rough, I think you might as well take 5 samples instead of 9 for your final render, saves some time again.

[Hannes]

Of course I replaced the water shader with a surface shader temporarily to check the foam distribution for example. But eventually I have to preview how the water looks in the end. Anyway Frank's trick is a great time saver!

[Dune]

Sorry to have taken you for a moron  I would have thought you used that trick!

[Hannes]

Don't worry, I didn't think you did! 

[Oshyan]

I was planning for RTE for your animation if it wins Hannes. But I forgot that the displaced sales might need to be rendered with the micropoly renderer for displacement...

- Oshyan

[Hannes]

Yes, you're right. The sails look horrible with bump only. Also the terrain looks weird.
Nevertheless I made a test (crop-) animation of the bow wave with RTE on and AA 2. What a timesaver!!! I'll post it later this evening.