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rohandalvi

Corona Render

24 posts in this topic

hi,

http://corona-renderer.com/

I dont usually post about new renderers, but this one really caught my eye.

Good enough to make me go back to 3dsmax after 10 months :(

It's a new renderer , still in alpha stage called Corona. It's a plugin for 3dsmax and it's currently free. It's also really stable, I have been using it for a week and it hasn't crashed even once.

Now the big question, why post it on odforce. Primarily because it's essentially a Pathtracer and it's ridiculously fast. Frankly i have never seen a path tracing renderer running on CPU, not GPU, go this fast.

You can never really compare render speeds between different renderers, unless they use roughly the same technology. Now, I believe that Mantra PBR is also a pathtracer, ( If I am wrong, please correct me.)

So I decided to render roughly similar scenes in Mantra and Corona. The model is pretty simple, Its a toy truck, with glossy reflections on pretty much everything, and two really massive area lights. Since Corona was happier to do it with two planes with a constant shader, that's what I used in 3dsmax. I am posting the images below.

The interesting thing is that the ray depth in corona is 25. It has a unified depth value for reflection, refraction and diffuse. In mantra, it was 10, 10 and 3.

Since corona is a progressive time based renderer, I gave it 6 mins to render. You can see the images to see how long Mantra took to achieve similar quality.

So anyone who has access to 3dsmax you should definitely check it out. You need to register on the forum to get access to the renderer.

regards

Rohan

P.S. personally I think Sidefx should just hire the developer, that way I don't have to go back to 3dsmax. :)

post-1625-0-26036900-1352567179_thumb.jp

post-1625-0-53467800-1352567213_thumb.jp

post-1625-0-73116700-1352567403_thumb.jp

Edited by rohandalvi
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Cool! I hope this kind of things makes the guys at sidefx to increase mantra speed!

But, one thing is render just one image, other is render a sequence. If you wanna continue with your tests, make an animation and render it with motion blur to see how corona will behave.

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The performance of GPU accelerated renderers is impressive. Equally impressive is their list of caveats like hair, motion blur, displacements, instances, volumes, programmable shaders and geometry attributes, graphics card memory limits, and so on. I don't think I've ever worked on a show or commercial that could be done with a GPU accelerated renderer. A few shots here and there but overall they're just not ready for production. The tasks they are superb for are product renderings and architecture since those often don't need more advanced rendering features like volumes and hair (or any of the other stuff that doesn't work with GPU accelerated renderers).

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The performance of GPU accelerated renderers is impressive. Equally impressive is their list of caveats like hair, motion blur, displacements, instances, volumes, programmable shaders and geometry attributes, graphics card memory limits, and so on. I don't think I've ever worked on a show or commercial that could be done with a GPU accelerated renderer. A few shots here and there but overall they're just not ready for production. The tasks they are superb for are product renderings and architecture since those often don't need more advanced rendering features like volumes and hair (or any of the other stuff that doesn't work with GPU accelerated renderers).

Corona is a CPU engine, still a couple of questions about features set rise, like programmable rendering engine, primitive versatility, motion blur and the rest of a gang mentioned by Luke. Another point is methodology, the scene you posted really doesn't say much about any renderer. Same as row parameter setttings (ray depth).

Could you post a hip file, to check out Mantra settings?

Edited by SYmek

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Corona is a CPU engine...

My bad, the eyes trick me and I thought the original post said "GPU not CPU" but it was the other way around. ;)

To sum it up flexibility and controllability are more important than performance to me. If I can have both that's great, but given one or the other I'd rather be able to get a shot done slowly than not at all.

Edited by lukeiamyourfather

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To sum it up flexibility and controllability are more important than performance to me. If I can have both that's great, but given one or the other I'd rather be able to get a shot done slowly than not at all.

That's for one, secondly 45 minutes is a timing PBR renders beautiful production frames in, including fur, not that basic example, thus I asked for a scene.

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Hi,

As it's still in alpha, there are a lot of things missing. Right now it doesn't even render particles let alone hair and fur. Also I believe they are aiming at architectural visualization as a primary market as a start so I don't know if a programmable render engine is very high up on their list. I dont think they are aiming for the film and vfx market in the beginning.

It does , however, have a proxy(render instances) and scattering system in place to do vegetation and stuff.

But there is no getting around the fact that Mantra is slow. The fact that corona took 6 mins when mantra is taking close to 40 mins, means that Corona is doing something right.

If Mantra can be sped up to the point of corona( for simpler renders), Houdini can be a used in a lot more markets. Because markets like Arch viz and product renders dont really need any of the stuff that film renderings require, like hair and fur, motion blur or programmable shaders. DOF can be easily faked in any compositing software.

I have always thought that Houdini would be great for Arch Viz. Once the building has been modeled, populating the scene and environment generation would be so much more easier in Houdini. But, there is no getting around the fact that for this kind of work Mantra is definitely not the best candidate for those sort of renderings especially when you have something like Vray around.

But if you have a renderer like Corona which can come close to vray like speeds while doing path tracing, it really changes the field.

And if Corona can do it so can Mantra. I have full faith in the wizards working at Sidefx.

I am posting a few more renders from Corona. They are all between 30-55 min range, but mostly towards product renders and arch viz. And with the quality I have been getting, Corona is certainly production ready for those two fields.

I am also attaching the hip file so you guys can take a look at it.

regards

Rohan

post-1625-0-97402700-1352635877_thumb.jp

post-1625-0-26602600-1352635957_thumb.jp

post-1625-0-08941400-1352636031_thumb.jp

dump truck.rar

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You forgot to lock the file node.

Just checking your mantra settings they are way off from what is optimal.

Edited by Erik_JE

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hi erik,

Sorry about the file node. That's why I added the truck.obj. Incase I screw up. Something I am usually prone to do. :)

Also It would be great if you could post a render which has better settings and render time. I still sometimes struggle with PBR as to the settings. Mostly I just play with the Samples and the min/max settings. I believe that the max settings is just an upper limit which doesn't really have much of an effect on rendertime. Which was why I set it to 64. But If I am wrong , do let me know.

The idea was to get it as clean as the Corona Render.

regards

Rohan

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This was 9 min 40 sec on my machine. i7 2600k.

Not saying mantra is perfect but getting images of that quality dont take 45 mins.

EDIT: Also i totally missed dump truck.obj was in the rar before :)

post-5363-0-74621800-1352645739_thumb.jp

truck.hipnc

Edited by Erik_JE

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Here is with gamma 2 as well. Did not have time to tweak the lights or colors fully to work with it but you can see the background is less noisy.

Same rendertime. One more diffuse bounce.

post-5363-0-78012600-1352648749_thumb.jp

truck.hipnc

Edited by Erik_JE

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I dont think they are aiming for the film and vfx market in the beginning.

(...)

But there is no getting around the fact that Mantra is slow. The fact that corona took 6 mins when mantra is taking close to 40 mins, means that Corona is doing something right.

I don't know anything about Corona, looks like a decent render (as many these days of equal and free access to knowledge and opensource components...) but you are missing the point. First, the market by choice of both renders has a crucial impact on what both of them will be good at, and the more specialized they are, the more differences in particular scenario they will have. This is exactly the (theoretical) reason, why Corona might (theoretically) be better at rendering static, triangles solely scenes, with no material overwrites, no displacements, no geometry attribute driven shaders etc, no deformation blur, AOVs etc etc.

Theoretically, because.... your comparison is inaccurate. This scene can be rendered in Mantra in less than 10 minute, with comparable quality on my old dual core laptop (Core Duo T9500) Divide it by at least 2 (or 4 actually) to get the spec of your Intel i7@2.66 and note, that quality of my try is slightly higher (but the resolution little lower).

ps

your renders are faulty, because you seem to be lighting and rendering in sRGB space. I don't know how Corona handles this, but generally speaking physically based renders are sensitive on color space issues. I had to adjust your scene for linear color space workflow, which significantly helps Mantra to resolve sampling noise.

[EDIT] Oh, I did it try on a workstation too (6 years old Xeon 5355 2x4x2.66Ghz):

Generating Image: /home/symek/Desktop/truck_mantra.jpg (768x431)

Plane[C]: Cf+Af[4] (16-bit float)

Render Time: 19:10.37u 2.83s 2:31.02r

Memory: 824.17 MB

post-744-0-17022800-1352649400_thumb.png

Edited by SYmek
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hi,

I am really glad that posted this here, because I got to learn some really nice things I didn't know about Mantra.

Firstly, Erik thanks about the Noise level parameter, never really tried that before. Got my render time down significantly, but what was 9.40 on your system became 30.21 on my system. I guess there is a pretty big difference between the i7 920 and the i7 2400K.

SYmek, Your render looks fantastic. pretty close to the result i got with corona.

Could you explain about the whole sRGB and linear space stuff. I know what they mean but where do you access them from in Houdini. Also would be better if you could just upload the hip file, so I could check out the changes you have made.

No need to lock the file node, just upload the hip file I will reload the File node on my end.

SYmek, I was basically just comparing the speed of a Corona to Mantra on a simple enough scene which wasn't dependent on any sort of attributes. But if the speed difference is just mainly due to my lack of knowledge, then that is really good news, because it means that I get to learn something new.

regards

Rohan

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hi,

I am really glad that posted this here, because I got to learn some really nice things I didn't know about Mantra.

Firstly, Erik thanks about the Noise level parameter, never really tried that before. Got my render time down significantly, but what was 9.40 on your system became 30.21 on my system. I guess there is a pretty big difference between the i7 920 and the i7 2400K.

SYmek, Your render looks fantastic. pretty close to the result i got with corona.

Could you explain about the whole sRGB and linear space stuff. I know what they mean but where do you access them from in Houdini. Also would be better if you could just upload the hip file, so I could check out the changes you have made.

No need to lock the file node, just upload the hip file I will reload the File node on my end.

SYmek, I was basically just comparing the speed of a Corona to Mantra on a simple enough scene which wasn't dependent on any sort of attributes. But if the speed difference is just mainly due to my lack of knowledge, then that is really good news, because it means that I get to learn something new.

regards

Rohan

Stick to Mantra if you want to render animation sequence with hair,fire,smoke volume and shit loads of geometry.Every week , there is a new fancy renderer popping up and they come and go.Mantra doesn't and you can thank me later.

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Excellent post Jeff, we always appreciate tips for more efficient rendering. Keep sharing your knowledge!

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My approach with PBR and Mantra these days is to set the primary Pixel Samples as low as you can to resolve the geometry detail itself and if there are fine displacements or high frequency textures, then and only then will I start cranking up the primary Pixel Samples if I can't resolve that "primary" detail.

Practically speaking you will hardly ever find production frames without motion blur and/or depth of field, thus you can safely get used to that a pixel samples will be at a level 8-12 at least.

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So this is one way to dial things in with PBR. First get the primary samples to resolve the primary direct lit surface detail to where you want. Then add indirect lighting by managing the max ray samples and the noise level on top of the base Pixel Samples. Simple and effective.

Thanks you very much for the really helpful info, that's really awesome information, since I am here I am going to ask for more tips :blush:.

I used the technique described above and it's really effective on non blurry reflective materials which is awesome! I get a lot of speed and very smooth results than just trying to simply crank up the samples but It seems for blurry reflective materials the rules change a bit unless you increase the pixel samples I always get the same noise result from them, I can be doing something wrong off course, so when I have non and blurry reflective materials on the same scene decreasing the pixel samples works really well for most of the materials except for the blurry reflective ones and if I increase the pixel samples I got the quality that I want but the render times increases exponentially a lot. Does it make sense?

How would be the workflow in this case? is there a way to set the sampling control per object basis? Any tips to optimize the speed in this case?

Thanks.

Edited by Mzigaib

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I have the same problem as Michel, but with volumes, when using raytrace. Hope the solution is the same....

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