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do object sizes affect rendering time? how much?

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do object sizes affect rendering time? how much?
on Jan 2, 2008 at 11:58:37 pm

Hello everyone! Happy New Year!

I am making this animation of 3 hockey pucks moving on an ice surface. The output will be in 720p 30fps

I made the shapes in Illustrator 3 circles (450 pixels in diameter) and 1 flat surface (2000x2000 pixels)

The rendering time for a 15 secs clip w/ shadows and motion blur on default settings is 32hrs!!!

- Do object sizes affect rendering time? how much?
- Can I save rendering time by making my objects smaller in size originally?

Thank you,
NguyenCat Le

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Jon Okerstrom
Re: do object sizes affect rendering time? how much?
on Jan 3, 2008 at 1:43:00 am

Hi NguyenCat Le ,

Lots of things can affect rendering speed... the number and complexity of the 3D objects, the size of the bit-mapped images you're applying to the objects, the type of rendering you're using (native or OpenGL), the processing ability of your computer, and of course, whether you use motion blur. Also, whatever else is going on in your comp could cause a hit.

Having said all of that, the estimated rendering time sounds really high.

If the rest of your comp is really complicated and intense, you might try rendering just the 3D objects alone and compositing the movie into the rest of the scene.

I would not advise rendering smaller objects and trying to scale the resulting movie to fit a larger comp. You'll lose detail and sharpness.

Tell us more about your system and your project and we may be able to give more specific advice.


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Zax Dow
Re: do object sizes affect rendering time? how much?
on Jan 3, 2008 at 6:37:18 am

Jon's point about super-complicated objects and large texture maps are good to keep in mind. However, two of the things you mentioned (shadows and motion blur) are the biggest render hogs.

The default 8-pass motion blur renders the frame 8 times, so it takes 8 times as long as no motion blur.

If you are rendering interlaced images that will also double rendering time.

Each shadow adds approximately 30-70% to the rendering time, based on what you set the size of the shadow butter to be.

Let's take a look at your rendering times. 450 frames at 32hrs = 4.3 minutes per frame. Take off the motion blur and you'll end up at 32 seconds per frame. That's a reasonable time with shadows turned on.

Hope that helps!

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NguyenCat Le
Re: do object sizes affect rendering time? how much?
on Jan 3, 2008 at 8:29:24 pm


Thank you for your answers.

I'm using the following system:
2 x intel xeon 3.2 GHz (it's old, i'm hoping to upgrade to 2 xeon quad core this summer)
4 Gig RAM
Windows XP Pro 32-bit
Geforce 6800 GT

The scene is just composed of those 4 objects (3 pucks, 1 ice surface)

The project itself is a game to be used during TV commercial time outs during hockey games. You have 3 identical pucks except for one of them got a sponsor logo on the back. The pucks get shuffled around and the contestant must guess which puck has the sponsor logo. You've all seen this type of animation. This is why I need to use motion blur on this project.

I'm not using interlace it's in HD 720 progressive scan.

I was thinking about recreating the objects in illustrator but making them smaller, maybe up to 50% smaller, then reimport the smaller objects in Pro animator, move the camera closer to compensate for the size reduction, and render the thing again; will that work?

Without motion blur, the rendering time is a tad under 5hrs.

Thank you for your help!
NguyenCat Le

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NguyenCat Le
Re: do object sizes affect rendering time? how much?
on Jan 5, 2008 at 9:43:27 pm


Interestingly my after effects file got corrupted :( So I had to redo everything...

Well I took the opportunity to recreate my objects in illustrator and drop them to half the size. The rendering time with shadows but no motion blur took 4hrs (vs 5 on the original project). But what's more interesting is: the rendering time with shadows and motion blur took 16hrs vs 32 before although I picked 6 passes only for the motion blur

Take care.
NguyenCat Le

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Lou Borella
Re: do object sizes affect rendering time? how much?
on Jan 26, 2008 at 9:14:29 pm

were the pucks all in one layer with one instance of invigorator or where they one their own separate layers with 3 instances of invigorator? This can make a huge difference!!!

If you had 3 seperate layers you should try putting them all in the same instance of Invigorator on one layer and use the group feature to animate them!!!

Lou ...

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