Brazil vs. Vray - how to get such nice details with vray?

[Long John]

hit me but im unable to get such detailed GI renderings with vray.
with vray i always lack details i get with brazil.

i know that i have to sacrifice speed for quality and that vray is much faster then brazil for good quality.

BUT... sometimes i prefer to have 10% better visual quality then 50% better rendertime.

i must say i don´t use photon mapping, not with brazil, not with vray.
i don´t like to setup photon maps and tweaking the settings takes to much time for me.

vrays direct GI is not as good as brazils and with irradiance map im unable to get the nice details in the gi solution.

what im doing wrong?
or is the brute force engine of brazil simply better for best quality?

[RErender]

Can you post some samples of what details you are talking about?

[percydaman]

well the thing about brazil is that its not as flexible when it comes to speed optimizations at an expense of quality. Im sure you already knew that. I used the brazil beta for along time before I switched to vray and Ive found that vray can get the same quality but once again you have to really up the settings to the point that the difference in speed between the two becomes ALOT closer.

I dont have the commercial version of brazil (was very irked when they decided NOT to provide a full featured demo) so I cant do any comparisons anymore.

[Long John]

i think there is no big difference in QMC quality between the free beta of brazil and the final.

don´t get me wrong, there are sure big differences between the beta and the final but imho not on the QMC quality.

i wrote already that vray has better speed (and a real good quality) but it lacks some details in the gi solution.

what i mean is, if you have some relativ small objects in your scene then brazil will create better diffuse shadows for these objects.

and you are right percydaman, i can get closer to brazils quality but then vray becomes very slow too and it still don´t reach brazils quality.

the differences are not big, sure, but visible for me.

[tom schuelke]

Hi Longjohn

I am of your oppinion. some time ago a also made a comparison of the two renderers. Bad thing always is, that i know vray much better. But i also had the wish, to get as detailed and crisp very small and brilliant details with vray, as i could get with brasil. So maybe we should make a thread here to upload a comparison scene, an post our settings, to see how to get the best out of vray.

While for me vray is overal the best renderer right now available, we should see if there are some tricks, to get as detailed results as in brazil even with the cost of speed. Only to be able to if we need it and have the time.

Right now i havn´t to much time . I´ll see next week.

greetings

Tom

[flipside]

Do you have to play with local GI settings in Brazil to achieve this detail? (don't know if they have this but this was a way to get more detail in fr)

How low do you set the clr treshold? This is very important imo for improved detail. But I guess you already knew this... Imo if you set min max to -3,0 (for +- 800*600px) and use clr=0.3, you have very good detail.

regards,

flipside

[losbellos]

brazil far not as good compared to vray.(dont get me wrong I dont have any problem with brazil) We have tested a lot with a friend, for example make a simple skylight scene. Render it with brazil and then switch to vray. Turn off secondary rays(none)(so 1 bounce calculated only) and you'll se the two render almost exactly the same, however vray much-much faster... (you can test a differences in photoshop using two layers and difference layer blend...) I think the bounces also play a role in it. Of you have only one, you could get better shadows in some case surly.

The shadow details, you dont need -3/0, -3/-2 far enough but play with the color/distance treshold. Tweak. You'll see it, find a good balance. Otherwise post a sample scene, and the result for brazil and vray. I am sure there is a lots of guy here who can make it better.

[Long John]

but i don´t speak about simple skylight scenes, i speak about detailed scenes with big and small objects.

to capture th fine details vray is not faster as brazil, if it can get the details out at all in brazils quality.

[losbellos]

please post a sample scene.
(I mean if you really interested to get some solutions (someone might know) but if this topic is just about opinions, then OK)

[Long John]

i will look what i can do.
but i have not much time and i can not give away a client file.

[percydaman]

would a simple greeble scene suffice?

[losbellos]

I dont have greeble plug, is that free?

[stefan]

For small detailed objects it might help turning the "use irrdaiance map" option off in its material. These Objects will then always be rendered brute force and have nice detailed shadows (at the cost of longer render times o´course). But you probably knew that.

Stefan

[PixelJockey]

Yeah. The Greeble plugin is free. You can find it at:

http://www.maxplugins.de


Or someone could greeble a scene, collapse it to a mesh and email it to you.

[flipside]

I don't think that greeble is a good example to test the ability to render good GI detail. Most problems occur when there are lot's of bounces involved that should create the detailed shadows.

I modeled a very simple scene in max: a room with an opening on the top of one wall. Inside the room is a table that gets lit by the bounced light that comes from outside (skylight). because the opening is pretty narrow, not many of the skylights first bounce will reach the table. Illumination is therefore a result of the bouncing of light on the walls etc. Here's a wire:


In real world, there would definately be visible shadows casted under the table and table legs. With simple skylight setup this is not the case. Even with high settings, the result is still very bad.
Here's one with irradiance -3,-2 hsphsubdivs 75, clr=0.2:


And one with -3,0 and the rest is the same:

this one rendered 11 times longer than the previous one...

A trick I use often is to place a vraylight inside the opening. This light can cast shadows and you can get away with very low irradiance map settings while keeping much shadow detail.
Here's one with a vray light:

This one took 2/3th of the time of the first one!

You can also make the vraylight a skylight portal but this doesn't work as well imo.

So I too find it very hard in vray to get nice detailed GI shadows in area's where only bounced light can reach. I don't know if brazil would handle this better though.