Why aren't people using Mental Ray

[nisus]

The DGS doesn't do transparencies, IOR values and no fresnel effect.

Its a good start, but the mib_glossy_reflection is better.

 

Says who? Have you checked it???

 

nisus

[Spacelord]

Says who? Have you checked it???

 

nisus

 

Ooh sorry I just checked it does have IOR and reflection, but still no

Fresnel effect. If I remember correctly (its been while since I used Max),

you could use maxs falloff material in the reflection to get the fresnel effect.

The DGS is slow and requires high AA settings, the mib_glossy_reflection

is faster for glossie materials.

[nisus]

Hi Invaderzim,

 

Idd. Tnx for checking ,-)

As far as I know, there is an automatic Fresnel effect build into the DGS material.

 

How do you activate the "the mib_glossy_reflection"?

 

rgds,

 

nisus

[Spacelord]

mib_glossie_reflection comes with Mental Ray its part of the base.dll.

Somes guys wrote the spdl files that give XSI users access to it.

So with max I'm not sure if some has written the declaration or whatever it

is that max needs to read it. maybe searching cgtalk might bring up something.

of jeff pattons site.

[Christopher Nichols]

Just to note... it is very easiy to do a AO in Vray... there are many way to do it, the most obvious is to turn make a white shader, turn on the environment light to 100% white and turn on GI with only primary and no secondary.

 

This is the image is MR at 8 min 19 sec

 

 

 

And this is it in Vray at 2 min 50 sec

 

 

Now if you actually bounce the light around a few times in Vray you get this at around 3 mins

 

 

Now it is true that Vray does not have a Dirt shader (yet) which actually makes for shorter rays and only darkens corners. A Dirt shader is different because of that control. MR even calls it a dirt shader (not AO). And it is still slower than Vray with bounces.

 

Vray, as it was shown ast Siggy last year, has one too. It is really a very simplistic thing, and IMHO, useless. The fact of the matter is that you can bounce light around in Vray faster then doing a AO pass in MR.

 

And if you do full GI in Vray with a true sky and true materials, you get way more lighting information in your image than an AO shader...

 

 

 

 

NOW... with that said. MR is an awesome package is an amazing tool. It can handle massive amounts of Geo, and has some awesome customizable shaders which I true admire. I think MR is one of the top professional rendering engines in the world and has some huge advantage over many others.

 

BUT AO is a joke. It was invented long long long ago during Pearl Harbor (the movie) by ILM because Renderman was way to slow to actually do GI. They needed a dirty way of coming up with a look of ambient light, and came up with a clever solution called AO. If they had the full power of GI, they would have opted for that by a long shot. AO is NOT the biggest advantage of MR. That is like saying that the biggest advantage of my car is that I have a hand crack in the front to start it.

[Christopher Nichols]

Addendum... here is a the same image with a MR dirt shader on it... (still slower then Vray with bounces)

 

[antonio_frias]

I'm glad to see your back Christoper, we hadn't heard from you in a couple of days.

Thanks for the free lesson! I'm always eager to hear what you have to say on these subjects.

[aaron-cds]

Wow, that pretty much eliminated any doubts I was having. I was starting to think I wasted my money buying VRay and giving up on learning MR. Thanks for the testing Chris.

[Christopher Nichols]

Wow, that pretty much eliminated any doubts I was having. I was starting to think I wasted my money buying VRay and giving up on learning MR. Thanks for the testing Chris.

 

Well if you buy my DVDs at Gnomon I have a lot more stuff to show you.

 

BTW there is an advantage to MR being "free." So keep that in mind.

[nisus]

Hi Christopher,

 

Although I'm into MR, we bought your dvds too. They arrived this afternoon ,-)

 

rgds,

 

nisus

[Christopher Nichols]

Hi Christopher,

 

Although I'm into MR, we bought your dvds too. They arrived this afternoon ,-)

 

rgds,

 

nisus

 

thank you... my goal is that conceptually that series of DVDs should you with whatever GI package you are using.

[aaron-cds]

Well if you buy my DVDs at Gnomon I have a lot more stuff to show you.

 

BTW there is an advantage to MR being "free." So keep that in mind.

 

I bought both of your DVDs 2 months ago. I'm almost through them. They're very good.

[pixelperfectg]

Chris,

I've found Mental Ray's AOCC shader much slower than actually using the same setup you used for Vray. In Mental Ray, simply put a white skylight in the scene, use a white material on the objects and turn on FG. From my own testing, I've found the render times (for this type scene) between Vray & MR to be very similar with this method.

And as an added benefit, since the MR AOCC shader only gives one bounce, the FG method can provide multiple bounces (Max7.5 and higher) for more realistic effects if desired.

I just thought I'd mention the FG method if you wanted to try that and see if reduces the gap in the render times in your scene.

Jeff

[Christopher Nichols]

Chris,

I've found Mental Ray's AOCC shader much slower than actually using the same setup you used for Vray. In Mental Ray, simply put a white skylight in the scene, use a white material on the objects and turn on FG. From my own testing, I've found the render times (for this type scene) between Vray & MR to be very similar with this method.

And as an added benefit, since the MR AOCC shader only gives one bounce, the FG method can provide multiple bounces (Max7.5 and higher) for more realistic effects if desired.

I just thought I'd mention the FG method if you wanted to try that and see if reduces the gap in the render times in your scene.

Jeff

 

Well I will mention a few things. I used the MR shader with long and short rays... the fact that yours is closer to the time in Vray is fine. Either way it still does not change the fact the AO is pointless when you can do GI in nearly the same amount of time. If I used QMC in Vray, I would have gotten similar times.

 

MR and Vray are probably (at the core level) the two fastest raytracing engines one the market. Vray on the other hand, has build on top of that one of the best and most versital GI methods which can give you the highest level quality GI in the shortest amount of time. So AO is pointless to use in a Vray pipeline to fake GI unless you are trying to use it for some sort of dirt shader.

 

BTW... AO is no bounce, not one bounce.

[pixelperfectg]

I completely agree with you. Just wanted to offer the suggestion of using the FG/skylight/and white material to the MR users here that may not have tried it before.

[Spacelord]

Thanks Chris,

I'll have to get your dvds one day, are they applicable to

other renders ? too,I guess I'd be able to transfer most of

your dvds to Mental ray.

Just so you know ctrl_studios have written maybe rewritten the AO

shader in Mental Ray for XSI. I haven't tried it myself, but I will when time

permits.

http://forums.cgsociety.org/showthread.php?t=358296

 

I don't want to scare people off Mental Ray, but for doing Arch Vis Vray

is the way to go.

[Christopher Nichols]

I completely agree with you. Just wanted to offer the suggestion of using the FG/skylight/and white material to the MR users here that may not have tried it before.

 

AH... sorry... yes, point taken.

[Justin Hunt]

AO is a Fake - It can not and should not be compared to bounced light, they are two entily different beasts. AO should be considered as a quick and easy way of simulating Sky Shadows. It does not bounce light, calculate color bleed, reflections etc. It is like comparing apples and oranges.

 

Christopher what are your AO settings?

 

NISUS - I use AO in the Diffuse Level slot of a Oren_Neylar Blinn shader, or any shader that has Diffuse Level. Baiscally what it does is generate the darkening effect of objects close to each other, giving greater depth and grounding to objects. The two important settings are the distance falloff - it must be relevant to your scene, smaller values are better, and the values of the bright and dark colours. If the bright is pure white it tends to overblow the material, similarally if the dark is black it over burns the material. The good thing with unsing AO at material level is that you can control it locally rather than globally when AO is used on an omni @ 0,0,0. Such as glass can have lesser values than say concrete.

 

The AO Only took 1 Minute and the fully textured and light render took 4, both at 1500X650px.

 

The Photon and Final Gather with AO took 15minutes and the Photon with FG, AO fully textured took 20 minutes.

[vizwhiz]

is it worth considering That mental ray keeps getting updated per max release cycle

 

whereas Vray is still waiting for 1.5 more Than 1.5 years??

 

just idle curiosity

 

i can barely afford free,

 

The lack of Tutorials should JP a really big market

 

To go after

 

Jeff, i am impatiently waiting for your MR Tutorials, hurry

we are getting Vray at work so i will also buy Chris' DVDs

 

Too

 

well, i will Tell The people at work To pay for This

 

randy

[Justin Hunt]

Thanks Chris,

I'll have to get your dvds one day, are they applicable to

other renders ? too,I guess I'd be able to transfer most of

your dvds to Mental ray.

Just so you know ctrl_studios have written maybe rewritten the AO

shader in Mental Ray for XSI. I haven't tried it myself, but I will when time

permits.

http://forums.cgsociety.org/showthread.php?t=358296

 

I don't want to scare people off Mental Ray, but for doing Arch Vis Vray

is the way to go.

 

A while ago I tried something similar in Max to simulate colour bleed with AO in a Reflection material. It turned out worked but by no means usable in production. It would have been quicker to do a high setting full blown GI render than using my AO colour bleed shader. I gave up, but ctrl_studios shader tells me that I was onto something.

 

JHV

[Justin Hunt]

Just another little test

 

First image is Photons and Final Gather rendered in 6:15 mins and the second is Photons, FG and AO and rendered in 16:57 mins.

 

JHV

[Spacelord]

Sweet Justin, keep the tests up.

Here's some renders I've done using XSI/mental ray 3.4.

Just showing I can do decent renders in Mental Ray just prefer to do it in VRAY.

Don't ask about time, they take forever to render with glossie reflections,

specially the interior ones.

 

[nisus]

Hi all,

 

FYI check the Autodesk E-course page... They have launched several good concept animations about MR. They talk about shaders, lighting etc... HIGHLY RECOMMENDED!

 

To Justin,

 

Do you render the images in one pass? or compose them afterwards?

 

rgds,

 

nisus

[Justin Hunt]

one pass, that is the nice thing with this methode is that you don't need to composit. That is not to say you can't.

 

JHV

[Justin Hunt]

Invaderzim - great work,

 

yes glossies are a pain in the A** when it comes to rendering. They have become the "Flavour of the Month" and I have seen far too many renders where they have been used to the extreame and very badly at that.

 

This is my first real result frim Vray. There are some major issues, ie grain, light quality and something weird with the timber floor. This took 45 minutes to render and before I turned off all reflections 6 hours and counting.

the dark one is a straight render and the other is lightend and brightened in PS

 

JHV