Rendering time just went up by at least a factor of 5


(Rhysy 2) #1

Another question about the trench I’m making (sorry!).

The current file renders a 640*480, oversampling 5 jpeg picture (no motion blur) in under 2 minutes. Fine.
Then I added some tower-mounted cannons to the main surface of the death star, in a line running along one side of the trench.
Rendering time still under 2 minutes (probably, in any case not noticeably increased) - fine.
Then all I did was I duplicated the line of towers, and placed them along the opposite side of the trench.
Rendering time is now over 12 minutes ! (I haven’t actually timed it because I’m too impatient to render anything that takes longer than it takes me to eat my dinner! :slight_smile: ). The picture doesn’t even begin to appear in this time. The black picture screen appears, and the computer’s thinking light flickers constantly, but that’s it.

This sudden increase should not happen, because :

  1. The new meshes aren’t that complicated.
  2. Compared to the number of meshes making up the death star surface itself, the number of tower-mounted cannons is negligible.
  3. Just to see if there was a limit on the number of renderable meshes or something, I duplicated the entire side of the trench several times (making several hundred new meshes), and there though rendering time was increased, it was not by much.

I am at a loss. I seem to be doing more wrestling than rendering with Blender lately. :frowning: Can anyone help ??


(dotblend) #2

just use duplivert

make a grid for the cannon locations
parent one cannon to that grid
duplivert, done


(Rhysy 2) #3

A good idea for easy organization, but it doesn’t affect rendering time at all. I don’t understand why adding a few more simple meshes has such a drastic impact on renderin time - please help !


(slikdigit) #4

You said

the computer’s thinking light flickers constantly

perhaps you’re running out of memory, and thrashing the hd?
if you’re using windows try running taskmanager and tracking memory usage during the render.
If you’re computer needs to swap it’ll run wicked slow. The solution? make the scene simpler or buy more memory. How much do you have?


(Rob) #5

Eat your dinner more slowly.

Rob.


(Rhysy 2) #6

Eat more slowly…ok. But what am I supposed to do when it’s rendering an animation - prepare and eat a five-course meal ? :smiley:

silkdigit is right, I seem to be running out of memory (I have 128 mb ram, but a lousy graphics card). Fortunately I can probably avoid the perils of simplifying the scene or buying a better card/memory by rendering the cannons separately and putting them in the background.

I guess I’ll never know why these simple meshes affect rendering time whereas the trench meshes don’t, but at least I can get on with it now.


(S68) #7

Don’t buy a better card. Card does not affect rendering times.

Buy more memory 128 Megs with windows :o Too little even for word processing :wink:

Stefano


(phlip) #8

I have a P150 with 32MB RAM and windows ME (Suggestion: never get ME), so I know all about slow rendering…:x

My solution:
Render at 25% with no OSA or mblur, and then when you’re done go 100%, OSA 16 and MBLUR if it’sa a movie and run it overnight. Even go all the way to 800x600 because it’s got all the time it needs. Even on my computer I rendered a 320x200 75-frame movie with OSA16+MBLUR and it had plenty of time to spare…


(RipSting) #9

OMG… go here as fast as you can
http://www.newegg.com/app/manufactory.asp?catalog=147&DEPA=1

Even I run out of memory sometimes… and I have 1GB of it! Usually I’m using too many dupliverted spotlights to get smooth shadows:) We’ll always be pushing the limits of our computers.


(Rhysy 2) #10

Wow, that memory is dirt cheap !!!
Maybe when I get a student loan I’ll buy some - but I don’t need any right now, I can overcome the problem by putting the death star surface or turrets in the background, depending on the camera position. Also I cheated a lot and moved them away from the trench so they’re not visible from inside it - problem solved.