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View Full Version : Doubtssss - with -CINEMA 4D Render Speed


zzmadd
06-17-2006, 12:02 PM
Hi,

I am new to cinema.
I am switching from maya. I am very happy.
I hate maya.

So .. I am rendering just the basic duck tutorial which comes with Cinema 4D.
I finished it, enjoyed it and so on.
But it's time for rendering and I am enxperiencing slow downs.
I am rendering at just 320x200 to check the animation and to see Cinema working.
The problem is some frames take 40 sec, other 30 minutes!!
Camera is steady, nothing different is moving in the background.
I am on a mac, with cinema 9.6.
It seems to me that the difference (much longer render time) happens when I "Hide" Cinema 4D and using the apple+H command ...
By checking Activity monitor, even when taking long cinema is taking 195% of processor speed.
So I don't know ... if it is in the foreground it goes fast otherwise not.
Doesn anyone know? Shall I renice cinema?

thanx

Srek
06-17-2006, 12:04 PM
Maybe your system is running out of physical RAM and is starting to swap out to harddisk? Or maybe you animated HN subdivisions or something like that.
It's realy hard to tell what is happening without beeing able to see the scene.
Cheers
Björn

zzmadd
06-17-2006, 12:15 PM
Well, the scene is the one in the Duck tutorial that comes with any copy of Cinema 4D.
It should be pretty well known.
Yes there are HN in the scene. The 2 ducks are HN.
plus fog

The point is that some frames are much faster than others .. with no apparent reason. From 2 minutes to 30 minutes ... and the scene is almost the same ...

well I don't know. I come from maya and there render speed has always been pretty consistent between frames...

zzmadd
06-17-2006, 01:57 PM
Maybe it is the HUGE shadow map used by the key light of 5000x5000
I quit and reopened cinema and now the average is at 3.45 min per frame .. so no 30 min frames .....

I wrote to maxon too

3DKiwi
06-17-2006, 07:24 PM
I've done the duck race tutorial when it first came out. At the time I was running a Athlon 2400 with 1.5gb of memory. I recall on the close up scene where the biker duck comes into the frame that the render times increased dramatically. In fact I've never finished rendering the whole sequence. The issue appears to be the materials on the engine and water and what they are reflecting. This frame here for example takes ages to render. Frame 113.

Cinema 4D has a very fast render engine. However the Duck race tutorial with its sky, water and clouds isn't a good example of this speed.

3DKiwi

flingster
06-17-2006, 08:30 PM
maybe it should be renamed the tortoise race...flame away...back ye evil flamesters...
does sound like an ill thought tut...fog, sky...and a high poly duck-beast, reflections everywhere...beginning to sound like the ugly duckling race...its all just wrong...wrong...wrong.:twisted:

imashination
06-18-2006, 01:56 AM
Maybe it is the HUGE shadow map used by the key light of 5000x5000
I quit and reopened cinema and now the average is at 3.45 min per frame .. so no 30 min frames .....

I wrote to maxon too

Well for one thing, there is absolutely no need to use a shadow map of 5000x5000, that is overkill. Remove a zero

Ernest Burden
06-18-2006, 02:26 AM
Well for one thing, there is absolutely no need to use a shadow map of 5000x5000, that is overkill. Remove a zero

That's so big it would probably render almost like a hard shadow. In fact, try rendering by just switching the shadow type to hard/raytraced and you'll know right away how much of a hit the shadow map was costing you.

zzmadd
06-18-2006, 02:30 AM
I was just following the tutorial.
They use a 5000x5000 shadow map because that key light is used for the whole scene.
The scene is huge.
~ 20000 units wide and heigh.
So they say a small shadow map would look very grainy ...
Yes indeed it is overkill, but also in another tutorial (very good one) from gnomon about digital environments, when you have to light and give proper shadow to digital environment you have to use a big shadow map on the key light.

Then if your shot will zoom into the environment showing detail, you'll have to use more lights with smaller shadow maps to get proper result.

imashination
06-18-2006, 10:36 AM
The scene size is not important, the important part is how much of the shadow is rendered into the final image. I havent done it myself, but it sounds as if they have a single light above the scene and are moving the camera and actors over a large distance. I'd suggest you try reducing the shadow map down to 500x500 and have the light move with the camera and ducks.

zzmadd
06-18-2006, 11:49 AM
The scene size is not important, the important part is how much of the shadow is rendered into the final image.

Yes .. here are the right words!
It makes sense.
Also when I am rendering from far above (so rendering almost all the shadow in the image) the rendering was fast.
When I was rendering from below a very narrow framing of the entire shadow map the rendering time where fluctuating from 3 min to 25 min ...

Anyway a different method has to be used from the one of the tute.
My initial concern was why the rendering timing were fluctuating.

thanx it was helpful

stew
06-18-2006, 07:07 PM
One of the rules of thumb that Jeremy Birn gave in his (highly recommended) "digital lighting and rendering" book is that when you have to go above a shadow map size of 1000x1000, consider using raytraced ("hard" in C4D) shadows instead.

Per-Anders
06-18-2006, 09:08 PM
or even area shadows will work very nicely (and probably take around the same time, thoughyou can optimize them a bit with experience). another sort of cheating option that doesn't always look so great, but can work for still is to use a raytraced shadows, render to multipass then blur the shadow in post (you can make it look more convincing if you make a render that uses incidence angle and a depth layer and use that to control the ammount of blur either as a mask or using a "compound" blur that will use that depth or fresnel render to do it's "dirty work"

Ernest Burden
06-18-2006, 11:36 PM
Or use a close 'light cluster' set to hard shadows. I want to test this out soon if I can find a few minutes to do so. I wonder how fast six lights can render with hard shadows vs one with a big map or area shadows. Test is best.

zzmadd
06-19-2006, 01:37 PM
Hi everyone ..
Just to close the topic I would like to report what Maxon replied to me.
They were amazing fast .. and solved the problem.
I am impressed. They are really prompt (released universal ver for mac in jan, plus OpenGL enhancements after OSX10.4.6 immediately)

here it is ...

"ok, we did some further tests with the scene "animation-close.c4d" and found that the reason, whysome frames render quite long, is that in some frames the blimp is reflecting in the engine of the motor duck. To increase the render speed, either disable the option "seen by rays" in the compositing tag of the blimp or to hide the blimp completely as it's not seen in the rendering anyway."

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