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IP and Importons


Crazy Homeless Guy
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I started a thread on CGTalk regarding some experimenting I am doing using Irradiance Particles and Importons in Mental Ray. I would have started it here, but there has been a lot of IP discussions on the Maya boards at CGTalk.

 

http://forums.cgsociety.org/showthread.php?p=5605169#post5605169

 

So far my experinece with them has been mixed. I definetly feel they are an improvemnt over other GI methods within MR, but they are not mature enough to even start encoroching on Vray's implementation of Irradiance Mapping and Light Caching.

 

As you can see form the tests I have done so far, I am having a lot of splotchiness, and a lot of artifacting that I have not been able to iron out yet. Perhaps this is why the are still a hidden feature in MR 3.6.5.

 

Anyway, just thought I would share this with the MR users here on CGArchitect. If anyone is interested in experimenting with them on this board, we should start a thread, complete with a test scene,and links to the files.

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Hey Guys,

 

Going off past experience, experimenting with 'hidden features',

unless done purely for fun, is a lesson in mucho frustration. :)

 

Lots of potential with them, but not exactly a mature toolset

just yet. IMHO ;)

 

Regards

Bri

 

I hear what you are saying, but part of the reason I started exploring this path is due to a potential approaching interior project. My work flow is predominantly in MR right now, but I am hesitant to use MR to produce professional quality interiors. It just doesn't reproduce diffuse to diffuse lighting like Vray can. So I have a choice of dropping back and using Vray on them, or taking the plunge, and trying to produce them in MR using Irradiance Particles.

 

We may wind up not doing that project, but since I am interested, I want to push IP with some tests, and see what it can do, and what it can handle.

 

Maybe I am an idiot, and dreaming. Time will tell. ;)

Edited by Crazy Homeless Guy
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I find Importons and IP really hard to tweak, specially if your using interpolation.

It looks great with no interpolation but takes for ever for AA part of rendering.

If it had some sort of preview like final gather has it might be easier to tweak.

 

 

Mental Ray is fine for rendering interiors, I don't really see the problem.

If you do a Mental Ray / Vray test it would be good to see your results.

 

cheers

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Not entirely certain I'd agree with that, certainly VRay is great on

interiors, but not many situations I have come across that MR can't

handle to an eqiuvalent quality?

 

I want to believe this, but I haven't had luck doing anything decent luck with MR on interiors. Nothing that I would put my name on anyway. I could work at it more, but the thing is, I haven't seen many MR interiors from anyone that I would want to put my name on. Maybe if there more inspiring images out there, I would change my tune.

 

I hate threads arguing about what is the best render engine, etc... They all have there strengths and weaknesses. Some things I love MR for, but interior images is not one of them. ....until I am starting to see the test images people are doing with IP. If MR continues development with them, and works out the bugs, I think it will be capable of producing some elegant interiors.

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I find Importons and IP really hard to tweak, specially if your using interpolation.

It looks great with no interpolation but takes for ever for AA part of rendering.

 

I don't find the settings in general to be to difficult to tweak, but I agree immensely about the interpolation. Without it, or for secondary, it looks great, but takes forever to render. With it, I get lots of artifacting and splotchiness. If I could get a smooth solution with it, I would try it on a production render.

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Thanx Brian,

I thought that's what you meant, but I just wanted to be sure...I wasn't aware MR had a problem with that, and I also didn't know FinalRender had overcome that problem...so have you found the animation presets in Vray have now solved the moving objects problem, or are you using another technique ?

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Mental Ray is fine for rendering interiors, I don't really see the problem.

If you do a Mental Ray / Vray test it would be good to see your results.

 

The tests results came out better than I anticipated. There was only one solution which I consider unexcatable. Someone may still proves me wrong on that, but I considered it antiquated technology before my testing.

 

The order I am going to list the methods used to render, do not match the order the images are in. I don't want people to be biased.

 

Mental Ray - Final Gather

Mental Ray - Final Gather and Photons

Mental Ray - Importons and Irradiance Particles

Vray - Irradiance Map and Light Cache

 

Anyway, those are the tests I have done so far, below are the images, again, they are not in the same order as the tests listed above.

 

Thanks to Brian Howard for posting the original model, and Jeff Patton, whose thread the test scene was taken from, as he re-hosted the model.

Edited by Crazy Homeless Guy
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if you want to see some awesome interior renders done in mr, hop over to www.mymentalray.com . Some of the best interior stuff around.

 

jhv

 

I am not completely happy with the interiors on that site. Some aren't bad, but most of them are more or less interior with large open windows. I feel those types of interiors are easier to render because the skylight can light a large portion of the room. A solution that makes good use of diffuse to diffuse bounce is important when I don't have enough exterior light, and possibly are limited on the lights that you have on the interiors.

 

Even the though the tests I did came out OK, they are not the perfect tests One because I didn't spend enough time with each method, and two because they have 3 lights casting around the room, so most corners are getting light on a first bounce, and by the second bounce 95% of the image has light. I need to set up a scenario for that room where there is one light in the corner, and maybe some dusk light coming through the window. I think that would be a good test for diffuse to diffuse bounce.

Edited by Crazy Homeless Guy
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I like the first 01.jpg.

I think the 02.jpg is using photons and FG, the white blow out under the cloth on the couch gives it away.

Not sure which 03.jpg is but I don't like the chair legs.

04.jpg looks pretty good

So you going to tell me the 01.jpg is VRAY :) hehe

 

Anyway I like your tests, keep them up.

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I like the first 01.jpg.

I think the 02.jpg is using photons and FG, the white blow out under the cloth on the couch gives it away.

Not sure which 03.jpg is but I don't like the chair legs.

04.jpg looks pretty good

So you going to tell me the 01.jpg is VRAY :) hehe

 

Anyway I like your tests, keep them up.

 

On the images posted.....

 

01 - Final Gather Only

02 - Vray - Irradiance and Light cache

03 - FG and Photons

04 - Irradiance Particles

 

The Vray, Mental Ray is not fully a direct comparison. They handle glossy reflections slightly differently between the 2, so that accounts for some of it. Also the Vray and IP had the best color toning. Because I didn't want color toning to effect the outcome, I desaturatred the images. This way we are onyl looking at the quality of the light, and shadows that are created by each GI solution.

 

....I am looking for someone who is really good at FG and Photon mapping. I am not experienced in this area, but I want to see if someone can get better results besides myself. Let me know if you are interested, or if anyone else is. I will just post a link to the file.

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I changed the scene a bit since I did the first test. I deleted the IES files that were in the previous scene, and switched to a photometric cone light that cast area shadows. I am going to use this as my base scene.

 

From here on out I will be posting the full frame rather than cropping it, and including render times and machine specs. I have been rendering on both dual cores, and dual quad cores, so my current times are a bit skewed when compared.

 

I have also been playing with the FG settings since I did the first FG render, to try and get them faster. That first one didn't break any land speed records.

 

The matte material also has a glossy reflection, which is true of both the Vray model, and the MR model.

 

http://www.crazyhomelessguy.com/_Misc/CGArchitect/LightComparisons/Light_Comparison_FG_05.max

 

ts.

Edited by Crazy Homeless Guy
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here's my first stab with my usual settings.

fiddled a little with the light, material and GI + FG settings.

 

2m 57sec on dual quad core.

 

Do you think you can post your settings, or re-post the file for investigation? I would like to look at the Photon settings, and also to test the file using area shadows.

Edited by Crazy Homeless Guy
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Here is another Importon and Irradiance particle study. I don't have the render time, as I left it render on one of the farm machines. It is quasi brute force, so I am guessing the render time was about an hour.

 

This is the setup where I was still using an IES light, so the light distribution is different.

Edited by Crazy Homeless Guy
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