Quick Brazil question

[Ian Jones]

min / max sampling will probably fix this. Set your min samples to about 2 max to 3. Will increase render times a bit.

[Ian Jones]

Oh yeah, also see the broader squares you are getting. They are bucket rendering squares. Decrease the size of the buckets to 16*16 and their effect will be greatly diminished. Setting is located in the Brazil general settings rollout.

[designgoblin]

http://members.shaw.ca/designgoblin2/braziltest04.jpg

I left the buckets at 64 but increased the smaples as you suggested. They could go higher still I think to remove what's left of the "noise" but that defiantely did the trick. Thanks for the assist.

DG>>

[Ian Jones]

hey cool... glad I was right. keep rendering!

[censored]

put the shade rate back down to -3/0, and instead increase the view rate.

[designgoblin]

...but increase it to what? I doubled it and the rendertime grew considerably. Adding to the sampling didn't seem to have quite as much impact but also added time.

My original question was..

"Are there other ways to eliminate this issue or some standard settings I should know to get smooth surfaces?"

...so can you suggest settings for the key render attributes for the scene above? Thanks.

DG>>

[Khepri]

Originally posted by designgoblin
...
My original question was..

"Are there other ways to eliminate this issue or some standard settings I should know to get smooth surfaces?"


quick awnser:

no

every scene is different.

its a trail and error thing with viewrate.

just try to work your way up the viewrate and see what it does.

this way you can easely see what setting gets you what effect.


cheers

[wurp]

Can you post the rendertimes and also the system specs please? for both images if possible

Thanks!

[designgoblin]

Well WURP, I did some tests with the viewrate settings (below).

As you can see, set at 60-70 should be about good enough (60 still had some patchyness in the deeper shadows). 100 is cool but took forever on my old box which is: 1.7 Ghtz P4, 1 Gig RAM, GF2. I realize this spec is lousy and is by no means a professional level render machine but it's all I've got right now to learn on.

I dread to think what would happen to render times with some reflection/refraction in there!!!:shrug:

Render 01
http://members.shaw.ca/designgoblin2/render01.jpg

Render 2
http://members.shaw.ca/designgoblin2/render02.jpg
DG>>

[designgoblin]

Render 3
http://members.shaw.ca/designgoblin2/render03.jpg

Render 4
http://members.shaw.ca/designgoblin2/render04.jpg

DG>>

[wurp]

1 hour and 18 minutes for a simple indoor scene?
You sure there isnt a faster way to render this with GI in brazil?
Maybe we can do a benchmark here between different renderers? Post the scene in .3ds AND .max format and with a null or small cube exactly at the position of the light, also put a null or small cube at the spotlights interest, if you used a spotlight that is. Also post the RGB colors for all objects as well as for the light.

[designgoblin]

There is either something I'm not understanding, or my machine is hooped somehow..but I agree, it's waaaaay too slow! And I've heard so many talk about how fast GI is in Brazil...it's why I looked into it after I tried out the slow skylight renders in Max.

I removed the bLight and placed two small cubes at the origin and target positions. I zipped up a .max and a .3ds version of the scene and put them HERE > > > (http://members.shaw.ca/designgoblin2/GItest_nobLight.zip)

The BLUE sphere is RGB:65/111/196
The GOLD sphere is RGB: 255/174/0
The BEIGE walls are RGB: 196/189/150
The WHITE sphere is just that.
The light is WHITE

All spheres have a specular setting of 30 and a gloss og 10.

..

I bumped up the detail in the sphere quite a bit but not enough to account for the slow renders..I hope??

Thanks for the help. I'm gonna take a look a VRay too I think!!

DG>>

[soulburn3d]

Brazil has 3 basic categories of GI, qmc, photon maps and photons + regathering. I tend to use qmc for outdoor gi situations, for indoors, I would recommend photon maps as a start, and regathering if you have a lot of small details that would benifit greatly from a more accurate solution. So I wouldn't use qmc for this scene, I'd use photon maps. Here's a photon map example, 4 bounces, rendertime 2 min 46 sec on my slow single proc AMD 1800, it would probably render under a min on a good 2proc machine.

http://www.neilblevins.com/temp/gitest.jpg

I'm working on a regathered version now, will post that when it's done.

Anyways, for tutorials on how to use photons effectively, visit your account page and check out the examples area.

- Neil

[censored]

I got a version of this down to 13 seconds using Brazil on a P4 2.8C - it looks very similar to Neil's - but I unfortunately screwed too much with the file and lost the correct settings, and beyond that, don't have an image host.

So you'll just have to take my word for it. :)

[drewbie]

Regathering is taking around 5 minutes on my single AMD 2100. I think designgoblin is using straight qmc for his renders, hence the huge render times.

[soulburn3d]

Here's a photon render with regathering:

http://www.neilblevins.com/temp/gitest_02.jpg

Took just under 20min on my single proc amd, would be closer to 10min on a dual. Notice some extra darkening under the balls, those are the details I mentionned before that sometimes get lost with the regular photon method. But for the most part regular photons work just fine in production scenes. Also, I haven't gone in and tweaked any of the ray acceleration settings. I had an ambient occlusion render that was taking 40min at 2k, played with those settings, and managed to get the scene down to under 10min!

Anyways, hopefully this will give you some ideas on some of the optimizations you can do with brazil to speed up GI, and I repeat, check your account page for more info on the wonderful world of photons.

- Neil

[soulburn3d]

Cool Drew, 5 min is quite fast, will have to compare render settings to see where I can get some extra speed :)

- Neil

[soulburn3d]

Oh, and just to note, that occlusion render I spoke of earlier was 10 million polys with tons of small details, which seem to be the bane of ambient occlusion renders.

Ok, I'm up far too late, time for some sleep. :D

- Neil

[designgoblin]

Thanks for the info all.

I'll be sure to check out those options for GI. Your renders (soulburn3D) are good, but lack the lighting detail I was hoping for..but then render times are much better. For test renders, your suggestions make loads of sense and I'll be sure to check out the examples. For finals though, I think it'll be overnight renders to look forward to. I'll play with the photons also, see what I can do to atleast come closer to my 1hour render quality. Lot's to learn still :shrug:

Thanks again!

DG>>

[soulburn3d]

Well, if I A B your best render and the regathered photon render, the detail looks almost identical, although your image is brighter, which can be easily fixed by increasing the photon energy. So regathering is probably your thing, and its way way less than an overnight render. :)

Don't discount regular photons though, I have some scenes I presented at siggraph showing off photon renders, I'll upload the results tonight when I get home, average rendertime was 2-3 minutes, which includes antialiasing textures and a skylight source as well as an arealight shooting photons.

- Neil

[wurp]

Another option you should look into is to combine a low GI-quality rendering (which renders fast but has no detail) with an Ambient Occlusion pass.

this way you will get very fast and accurate renderings. Since real ambient occlusion isnt undersampled it will catch even the smallest details.

This method is something like 10x faster than full blown GI with the same accuracy.

I use mental ray in xsi but surely you can do the same with brazil.

Another nice thing with AO is that it wont flicker in animation.

http://www.renderart.net/temp/ao_comp_full_glow.jpg

[drewbie]

Here's two shots of regathering. The first is the 5 minute render. Still some minor noise, but it could probably be smoothed out with some of the GI parameters. The second is a 10 minute render, where I just upped the view rate a bit to smooth it out. I couldn't open the file (guess it's max 5) so I imported the mesh and set up my own light and camera.

http://www.utzweb.com/cgtalk/5mins.jpg

http://www.utzweb.com/cgtalk/10mins.jpg

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