Slow going on a "simple?" object

[J_Bug]

I've been testing an animation I plan to use in a short MiniDV movie I'm currently working on. This short clip consists of:

Geometry = A Renderable Spline and a 64 face Plane

VRay Features = Displacement, Motion Blur, Non Interpolated Glossy Reflections, Two VRay Lights and an HDRI (instances set differently for Reflections and GI)

I'm not using Secondary bounces with GI, my reflection Max depth is set extremely low at 5 and Reflection Subdivisions are also set to 5.

I canceled my animation this morning when each frame was running about 15 min. IT seemed as if every consecutive frame was adding a minute to the render time. I've attached some images and the animation below for reference.

Can anyone give me tips to speed up this specific situations?



http://www.dtoxx.com/J_Bug/Trinket_04.avi
Please right click and download the file as apposed to just running it thanks



What could be making this render so slow? I'm sure it's me

Thanks in advance,
--Jon

[RErender]

I would think it is just the price you'll have to pay for MB and Glossies, how long is the render time without MB?

[J_Bug]

I'm still doing tests but it seems to be about the same time. I'd say 14m for MB and 12m without.

I wonder if it could be the fact that I'm using a high res TGA for the displacement. For some reason it seems to be a combination of the Displacement and the HDRI. Does that sound like it could be the case or maybe I'm way off base.

I know that combining the glossy effect has its slowdown but 12m a frame seems a little odd.

--Jon

[RErender]

Have you tried killing "generate GI" for the objects?

[DaForce]

have you tried using interpolated glossies?

[vlado]

Try using the Fixed AA sampler, it might make things faster. *Don't* use interpolated glossies with motion blur.

Best regards,
Vlado

[DaForce]

vlado:
What happens when you use interpolated glossys and motion blur?

[PATER]

@J_Bug: I had a scene with a flycam, lots of trees... a lot of small stuff that bugs the Anti Aliaser. I changed the AA from Adaptive to fixed two level and my rendertime was just 1/3 of the original.

Motion blur and lots of perpixel fuzzy stuff like non interpolated glossy computations "kills" the adaptive AA and simple two level or fixed rate works a lot faster.

Looks cool your animation

@vlado or everyone who can help me: What exactly does the simple two level AA? The adaptive AA examines every region and places it's samples based on the variation of the pixels, right? What does the simple two level then? There is a base value, a fine value and a threshold so it has to decide where to put the fine samples. Where's the difference to adaptive?

Thanks in advance

[flipside]

If you think the problem is hdri related, why don't you just loose the hdri for the lighting part? I don't see why you need hdri in a scene like this, it would probabely look the same with a single color skylight, no?

[J_Bug]

Thank you thank you thank you all...

I did run into problems after more testing and now I see it must be interp glossy and MB. Thanks for the tip Vlado.

I couldn't get favorable results from interpolated glossy reflections even without MB. Must either be the nature of the displacement or that I havn't had much work with this technique and detailed objects

I'm going to have to avoid these tests for the next couple of days due to a tight shoot schedule I have to organize around on Fri from 5pm - 8am on Sat Shoot times are really rough when you can't pay anyone

Thanks again and I'll let everyone know how it turns out

RErender: I did and lost a minute or two of the render times.

flipside: These are just tests but I'll have a custom HDRI put together for the final. One of the locations is a white bathroom and you may be right... I'll have to think about this some. Luckily I'm also the DP on the live action plates First time for me so wish me luck.

PATER: Thanks for AA info... and thanks, I had to hand animate it cause I don't have Reactor. Not even sure if Reactors rope sim would do this though

BTW, the movie’s going to be very short and no big production but I plan to use VRay in every way possible to help make it look as good as it can (with a little help from my friends). I'm just afraid that the renders may look to good for our low quality camera and first time lighting attempt

--Jon

[samuel_bubat]

hi,

I think in this case you can also decrease reflection depth to about 2 or 3... shouldn´t be a visible difference.

I also wonder about the good quality of the animation with just 5 glossy
reflection samples. I remember (long time ago )other renderers that produced heavy flickering... when the samples were not extremly high.

however.. nice animation

sam

[J_Bug]

Thanks Sam

Yes I was happy when I learned that little fact about the refl subdivs. I believe GoncaloP passed that on to everyone. I plan to up the value a bit in the end. I have it set low now and I was almost sure it posed no problem.

As a follow up, I've modeled (no displacement) the trinket and it renders much faster, less than 2min a frame . I'll just have to wait for the next build to see if the new displacement can be added to this animation. I sure hope I can afford the render increase. Displacement adds so much more to the realism than my simple model

Thanks all

--Jon