Hi there, I keep on reading once and again how the Carrara render engine is fast as a bullet... In my case, i can't really go bigger than 2000x2000 simply cause it takes ages to render!! I've dumped the idea of GI, cause it takes too long! It might be cause I use high res textures on my models, and because i'm quite picky with bumps... (i have them almost everywhere!). So... is it normal for CS3 to take 5 hours to render a 2 spot light scene...? What's going on here!!

I'd say that when i just got it, it rendered a bit faster but maybe cause I didn't use as many bump maps as i do now.... Is that the problem? What am I doing wrong?!?!?!

My render settings usually involve no Skylight, nor Indirect light, nor radiosity... (all had to be dumped to quicken things up). I usually notice a BIG decay on speed when the engine gets to the hair... it just gets stuck!!). Thx in advance.

(Oh, and I have my drivers updated and all... could it be too little HD space? 20gigs on a 80gig HD...) Mmmmm......

Message edited on: 11/15/2004 12:04

Can you give us more details? Complete scene specs, system specs? How big is the scene file? Things I render with GI, and I do some high poly and texture mapped scenes, and it generally never goes over an hour for rendering.

Brian

Message edited on: 11/15/2004 12:13

I run a PC with WinXP Pro, a P4 at 2.0Ghz, 1gig of DDR Ram, an Nvidia Gforce4 Mx 440, and... two 80gig Hds (with too little free space.. :S)

I use CS3 updated to 3.0.4, and the scene I'm working on lately has, a few (low polycount) 3DS models of furniture, a Poser imported figure, with hair and clothing (trans maps, bumps and all...). Some textures (skin and some clothes) are quite big (around 4000x4000) including their bump maps. There are just 2 spot lights (with soft shadows on), and the render settings are as follows:

Full Raytrace:Off
Shadows, Reflection, Refraction, Bump, Transparency, Light thru Trans: All ON
Antialising: Fast
Object Acc: 4px
Shadow Acc: 4px
Filter Sharpness:100%
Max Ray Depth:8
Skylight: Off
Indirect light: On 100%
Photon Count: 5000
Light Quality: Preview
Accuracy: 16px

The rest is OFF

Basically is a FullBody portrait indoors. Any more info? Hope that's enough! :D

Thx. **After waiting for hours in front of the PC for renders to finish, I had to forget the idea of using GI or anything fancier... that's why the settings are SOOO basic.

Message edited on: 11/15/2004 12:36

Well for one if you want to render out a 2000x2000 size image as your final. You definetly don't need anything close to 4000x4000 for your texture size. Thats one thing that might be slowing it down. Whats the poly count in the scene? Brian

Mmmm... yeah, you're right, It's quite obvious that I don't need such a hi res in textures... But if I downscale, am i not losing much detail? Polycount, 22 objects, 320000 facets...(??)

22 objects? Not that the amount should effect it much. But make sure you have removed unused objects as well. I'm not sure what else to tell you. I'll think on it today. Perhaps someone else can come up with some other ideas. It doesn't sound like that intense of a scene, and with your settings I'm not sure why its taking so long. Brian

I'm worried about the hair... the render just gets stuck when it reaches this area... It's the Akina Hair for Poser, anyone has had any problems with it?

Hi, Light thru transparency can be really painfull to compute sometimes. If u try to use that feature with many CS3 trees, when you'll be stuck for hours to render them :-( BTW Did u check if the "no light when fully transparent" was check on your hair texture ? This might speed up the render ? Anyhow, using bump really slow down also the render...and that's probably reasons like that that made Eovia introduce the network rendering capability with CS4 pro... Anyway that's just my 2 cents ... :-) Pete

Attached Link: http://www.renderosity.com/messages.ez?ForumID=106&Form.ShowMessage=1989480

Ikercito, GI renders with bump take a long time to render in any software and Carrara is no exception - it's very complex mathmatically. It simply makes Carrara do ten times the mathmatics to figure out diffusion directions and color transfer. When you add transparency masks, like with the Poser Hair, You can really make Carrara work. To avoid long render times on my GI renders, I will usually deactivate the bump channel on most objects that aren't close to the camera. Instead, I'll move the bump maps into the Shininess and Highlight channels and ajdust to fake a bump look. Also, nicholas86 is correct in suggesting a second look at your texture map resolutions. The greater the resolution, even if the object that has it is a long way from the camera, the more carefully Carrara will calculate light effects. The attached link shows how to think about resolution of texture maps. Try to avoid bump on transparent objects too. Instead, imitate it with highlight, shininess and reflection if you can. Otherwise, hair will simply take a little while. Saving multiple texture map resolutions takes a little time, but it is easily made up for in rendering time saved.

Forgot to mention that you may want to bring your Filter Sharpness back to about 75%. At 100 percent it can cause strong aliasing in your final image.

Still no luck whatsoever! I rescaled all the textures, and checked the transparencies, removed the bumps and applied Mark's "bump to shininess/highlight" trick, but my render is still too slow... I improved a bit, but that's just it, "a bit"... grrrrr.... After fiddling this much I discovered a nice effect, from appliying the bump map to the reflection channel and setting it very low (5%) you get some great looking shininess on the skin! I've been trying to get this natural "oily skin" effect for a looong time, and seems like I'm on the way. At least i learned something new. :D I'll keep working on this scene, thank a lot for your help, keep it up!! Ike.

I'd take another look at your system and setup. I used to get a speed brake like this when Bryce ran over RAM and started using virtual memory -- is there a similar thing that can happen on a PC? I'd expect from one to four hours for my machine to render the scene you describe. And my clock speed is less than an eighth of yours (G3, 233 Mhz). So there is definately something wrong here.

I am using the computer --and Carrara--for enjoyment. If my imagery wont render,at the worst, in ten minutes I know the problem is ME! Please show an example of something so worthwhile to wait 4 hours for it to render!

Oh, it's nothing too spectacular...I stripped down the scene too see if it would render a bit faster, and left it overnight... here is a small pic!...

I don't know that I can help much here but I can give some of my observations. My scenes take from overnight to 3-4 days to render at 3000 pixels wide, often with no GI or indirect lighting. I just thought this was normal. Maybe if I paid special attention to texture map size, bump and so on I could get it down. I have also found that when the computer starts accessing the hard drive (memory swapping) the rendering drops to a crawl. With 1Gig of memory this should take a while but... I have also noticed that if C3 starts memory swapping and I stop the render , make a few changes and re render, the memory is not released and it seems to start swapping almost right away. I must exit C3 and restart to get the memory used back down. If you can't get your renders to go faster rest assured that at least one other person has the same problem! ;-) Ed

So you CAN hit that same bump with a PC -- when it walks out of RAM and starts spinnng the hard disk. That is an incredible slow-down when it happens. Minor things that can help include deleting parts of the mesh that aren't seen, setting fall-off on lights, reducing the photon count, reducing the bounce number. Soft shadows take time in all applications, and radiosity is, not surprisingly, a hog. I still see no reason I couldn't render that one over lunch...and as I said, my machine is two generations older than yours.

Wow sailor, I'm impressed to see I'm not the only one with looong renders. I thought everyone else had their pictures rendered much faster....!! But I mean, even if poser renders have muuuch less quality, they usually take no longer than 10 minutes! I know that certain features that don't show up much in a better render take a long time to be calculated, but... i don't know.. I'm not using too high quality settings... just soft shadows in the only 2 spot lights... However, i'll have to check if its a memory swapping problem... can I change the HD from where CS takes the virtual memory?..I've got two HDs... will that help? Thx! BTW what do you think of the render??

Ohhh, that's it.

I didn't think to ask and now I see it in your first post - I should learn how to read! Soft shadows and multiple transparency layers, like the kind in hair, absolutley kills render times. Try that render again without soft shadows engaged.

Fun render by the way!

Message edited on: 11/16/2004 16:16

Ikercito, Listen to Mark: he's the Man! You can change the swap file location in XP but few bother with it. I just always make sure I have as much as possible free on the swap drive. 500MB or more. Don't forget to dfrag once in a while. BTW your render is great. Ed

Soft shadows....drives render time up REAL fast. Photon count likewise (I had to roll my "First Quest" pic up to 8,000 photons to get smooth coverage on the walls). Transmapped materials when there is light interactions (that is, radiosity effects). But this was my experience; with comparable settings, faster than Poser4. With GI switched on, faster on a comparable scene then Bryce4 with a thirty-light skydome.

LOL Mark! Don't worry about it, as we say here in Spain "it's better late than never!". So now i know, soft shadowsare the problem. And maybe you have too much stuff to read Mark! Relax your eyes! you're too kind and too helpful to us the ignorants!! :D So, about soft shadows,... isn't that option too hidden under the menus and tabs?!?! I always turn it on and then forget about it...i can't stand harsh shadows, i always use softboxes in my photos!! Does the light radius affect too much render times? Oh, and my photons have never moved! It's at 5000 by default and never touched it.. bless my 3d-ignorance :D Thanks everyone, as always, I'll keep trying...!! Ike.

I've been seeing a lot of wild claims about Carrara being fast at rendering. Truth is, I find it quite a bit slower than Vue.

Render speed comparisons are often apples-and-oranges. I remember when Poser4 users used to laugh at Bryce4 users. Sure, Bryce was slower (Bryce has in fact some deadly inefficient algorithms)....but we were doing ray-traced shadows and reflections and proceedural materials in that time. Poser didn't even have real shadows. No matter what the application, to get speed you gotta turn down performance. To get all the bells and whistles you have to sacrifice some time.

If you are using GI you definetly shouldn't need soft shadows selected. Mark had it right on the dot, sad I missed it!!! Brian

I'd be interested if someone did a test for radius of soft shadows as it effects render time. Actually, that's something that bugs me about every 3d application I've used. There's no chart at the back showing the basic structure of the algos, giving the ray depth and any other hard numbers they can generate. Is up to end-users to set up physics labs and light labs and post their results at BBS's. I happen to like skylight a lot, and use that instead of multiple lights when I can. Skylight gives a wonderfully soft affect without the flattening of ambience.