I have been rendering some of my old images in higher resolutions. (High res? yeah right.. just enough to make an 8X10 print!:-( One has taken 6 days with the HD accessing the paging file almost continuously. Does anyone have any idea what the hardware consequences of this are? Dell notebook with 512M memory 1.6G intel. Thanks Ed

Hello Ed, Hi-res can mean many things! Not knowing what your settings are, doubling the size of an image can result in 4 times the render time. Before I kick of my hi-res stuff I try to minimize settings as much as possible. Unless there is some deep transparency, I reduce the ray settings to 4 vs. the default 8 and un-check all of the options I don't need (Light through trans, refraction, etc.)Why make Carrara do the math for rays I don't need. Also, changing the anti-aliasing settings from Fast to Best will cause a huge render time increase. Good is usually good enough. Same thing for the Global Illumination options. Can you see the image render progressing? If it's not advancing, I you might be the lucky winner of a rendering crash. I actually just had this happen in one of my renders because I moved a shader texture map prior to rendering. Carrara started but couldn't find the map and hung. The system was going full speed but since it couldn't locate the map, it didn't progress. Moving things back where they were fixed the problem, although I had to restart the render. Good luck! Mark

Mark, Thanks for the reply. The settings were lowered but the poly count was just too high. It was my blackberry (ref. my gallery) image. The large number of Anything Grows objects makes for a lot of polys. The render completed ok and my machine is ok. I was just wondering if frequent hard disk replacement was something I should anticipate doing so much 3D rendering. Ed

Glade everything turned out ok. Never had to replace a hard drive here and I render virtually every day - mostly 15M to 30M images... I think you'll be ok! The only thing I've been "forced" to replace is slow CPU's. Mark

Thanks. Guess I'll have to get one of those things they do the global weather simulations on. (grin)

More RAM means less virtual RAM (swapfile read/writes) which means less hard drive access. A faster hard drive means faster read/writes which means faster renders (in cases where RAM is at max size).

I do ALL my images high resolution for print at 8.75" X 11.25" (to account for bleed --- The trim size is 8.5" X 11"). What I do is set my Carrara render output to match the Photoshop pixel size/count I am after. For example an 8.75" X 11.25" image at 300 dpi is 2635 pixels by 3375 pixel (inside Photoshop). In Carrara I set the render output pixel size to 2635 pixels by 3375 pixels at 72 dpi. That was 72 dpi NOT 300 dpi (if you input 300dpi you will be sorry). Select Keep Proportions and your image should turn out to be about 33.8 mb. Not that bad for a single image. I then render the image, usually as a tif. When the render is complete I take the image into Photoshop. The image size is 36.458 inches x 46.875 inches at 72 dpi inside Photoshop. I Then change the size to what I am after. All I do is constrain the proportions and set it to 8.75" X 11,25" at 300 dpi and I have high resolution image high enough for high end printing. It ususally does not even take very long to render.

I was rendering 3000 pixels by 2745 at 72dpi for a .bmp file size of 23.5 mb. About 1 billion rays launched if memory serves. Which brings up the question (OT I guess) why does Carrara allow input of "dpi"? If you specify the pixel dimensions of the image the dpi is meaningless isn't it? Always Confused, ED

Pixel is for screen/monitor use. If your DPI is 72 already, then yes, you only have to tell what the dimension in pixels is. I only do 1024 x 768 pixel images for what I need (desktop background images). Maybe HDTV has more than 72dpi? If you print that 3000 x 2745 72dpi BMP image of yours on a 300dpi printer, how big is the picture? 10" x 9.15"?

I've always wondered how come changing resolution(dpi) increases rendering time if the size in pixels remains the same? If monitors and TVscreens use pixels for measuring sizes and resolution is mainly used for printing then why do they (monitors and screens) have a resolution of 72 dpi? 3000 x 2745 pixels at 300 dpi equals to 10" x 9.15" like you thought, Shonner. It doesn't matter what resolution you use while rendering. Printing at 150 dpi creates still quite sharp images if you want to get fairly good big prints with less rendering time. You are lucky to use inches in everyday life, we use the metric system here and I must always do more calculating when printing images because every program shows resolutions as dpi.

Go into Photoshop. Find out what the image size you are after is in pixels at 300 dpi. Then go inside Carrara/render/output and enter the pixels you got from Photoshop. Keep the resolution inside Carrara at 72 dpi and then select keep proportions. Pixel aspect ratio remains at 1. Then render. The output image will be a very large 72 dpi image. Open it in Photoshop and set the inches to what you are after and then set it to 300 dpi. This method produces wonderful sharp images ready for print after you convert to CMYK of course. It works without fail everytime. No need for any extra confusion or effort. Good Luck, steama

Resolution is resolution. Period. This thing with Carrara listing size in pixels, then @ resolution is silly. DPI is used for PRINTING only. Inches (or centimeters) X dpi is the resolution of the image. Or the image can be specified in pixels. (I.E. 1024x768) What Carrara does is assume your at 72 dpi on your computer, then if you change the dpi setting, they multiple by the difference to arrive at a different resolution for the image. What steama said about resolution is right on: "What I do is set my Carrara render output to match the Photoshop pixel size/count I am after. For example an 8.75" X 11.25" image at 300 dpi is 2635 pixels by 3375 pixel (inside Photoshop)." 8.75" x 11.25" @ 72 dpi = 630 x 810 pixels 8.75" x 11.25" @ 300dpi = 2635 x 3375 pixels Then he goes astray... "In Carrara I set the render output pixel size to 2635 pixels by 3375 pixels at 72 dpi. That was 72 dpi NOT 300 dpi (if you input 300dpi you will be sorry)." If he set the image to 630 x 810 @ 300 dpi, Carrara would create the same image as 2635 x 3375 @ 72 dpi. Check the Image Properties box located right under the Pixel Aspect Ratio in the same image size box. If you doubt me, give it a try. I just did. (Please note the screen capture.) Carrara should NOT have that little setting in there. It is misleading and confusing! There. Got THAT off my chest. Thank you for playing. Now please return your stewardest to her original upright position, and prepare for landing. ;> Hope this helps!!!!!

I think the Carrara Render/output tab is odd. It does work weird (but it works). That is why I use the final dpi size that I will end up with in Photoshop to render in Carrara. All my images end up in Photoshop anway. A little adjustment here and there in Photoshop and it's done. Simple as pie. i do this almost everyday. I would also say it is a fair bet that ultra long renders, renders hardware wear. )-: Regards, Steama

Right on bluetone! That simple experiment explains the whole thing. I will continue to ignore the dpi box. Slightly less confused, Ed

I suspect that it's just something the C developers intended to make more functional and then missed (like the NPR presets which aren't). The obvious thing is to have a drop down of units (in, cm, picas, pixels) so you can choose. Then the dpi would make sense.

Agreed. Then the settings would all have meaning. 8.5 in x 11 in @ 300 dpi. Just what the client wanted! (I also wish they had made those presets! I've wasted a lot of time trying to figure out how to control that puppy. Made some REALLY weird images in the process! LOL!)

It has just occurred to me what bluetone has really told us: If you enter the desired picture size in INCHES in the "height" and "width" boxes and the desired resolution in the "dpi" box Carrara does the math and comes up with the proper pixel dimensions. No Photoshop required. According to the manual (always the LAST place to look!) you can put any units in the width and height boxes. Seems to me though that a 100cm X 150cm picture at 200 dpi is really confusing at least for us Americans ;-) Ed

Does that work for you Ed? All I can enter is pixels. How do you tell Carrara that you're entering inches rather than picas or cm? Certainly the manual says you can do it but I've yet to find a way. Mark

Hey sailor ed. I just read the same thing in the manual. I would love it if this feature would work. I am using Carrara 3. When I try to enter the desired units (inches or centimeters) it does not work. The fields won't accept input of any units of measurement, just numbers. Any tips to make this work like the manual states? steama

Jeeeze am I a dummy. No it does not work! That'll teach me to jump to a conclusion! And to believe the manual! I will not delete my "foot in mouth" comment so that others may learn by my mistakes! ALWAYS confused, Ed

The manual tortures all of us! Not your fault at all. LOL Have a great day, steama

Thanks Ed, you had me worried there for a moment. ;-) Here's a challenge for anyone with time on their hands. On page 564 of the C3 manual there's a nice picture of the Output Settings for the Render Properties. Here's the challenge: all you have to do is to match the numbers in the boxes AND get the same result in the Properties box, ie. width 144, height 144, resolution 200 dpi giving an image of 640 x 480 pixels. Have fun!

Carrara 3.0.3 has a bug that fills in the wrong properties for the render resolution when you open a CAR file that you rendered once already. It still remembers what resolution you used last time. It just doesn't bother displaying that info in the properties.