Rendering is Labor Intensive

[Bill Tillman]

As a new inhabitant in 3D land, I'm finding out several things that are quite disheartening:

 

1. Rendering is a very memory intensive process. My computer is not the fastest in the world but this AMD64 Athalon 2.4 Ghz with 896M of RAM is not exactly a slouch. The rendering I attached here took just over 22 minutes to complete at 1024x768 + Presentation mode. I know this is the max settings but quality is what I'm after and I had no idea that it would take so long for a render to complete. It makes me wonder what the big architectural shops who render an entire high-rise building with landscaping, cars and people put up with.

 

2. My son has a nasty habit of surfing carelessly on the web so I had to install McAfee on his computer. I found that with virus and spyware scanning enabled this same rendering on his even faster P4 - 2.7 GHz machine with 512M memory took almost 45 minutes. Virus scanning is ovbiously a real detrement to rendering.

 

3. While the computer is rendering it's like watching paint dry on the wall to try and do anything else, like surfing the web or even playing a game while I wait for the render to complete. This again was not what I was anticipating with what I consider to be a higher end machine.

 

4. When I save the file from within AutoCAD I set the sliding scales to the highest quality and end up with a file about 350K in size. But then when I open the jpg file with my image editor and save it, the size of the files goes down to less than 50K with apparently little or no loss of resolution.

 

5. I still have lots to work with to get this gazebo in the shape I want, especially with the shingles on the roof surfaces. But I was wondering if anyone could advise me on how to acheive finer graphics with this, like ray tracing, or filter type, etc... which works best in your experiences. I'd like to make the image a little brighter. I don't mind waiting all night for a render to complete if it helps acheive a realistic image that makes the clients go "oooh, aaaaah, I want to buy one of those."

[Cad64]

Bill, you need a major RAM upgrade. 896MB of RAM isn't going to cut it when trying to render. The more RAM you have, the faster you will be able to render. Upgrade to 2GB or 3GB and you will see a significant drop in render times.

 

As for your question about shops that do large scale renderings. They have render farms set up to do this. A render farm is a network of computers whose sole purpose is to share the burden of rendering these large complex scenes.

[Cadfisch]

Bill,

You seem to have a memory problem. The image you attached must not take more than a minute to render. When I render a whole building with a very fancy wood/steel construction, timber cladding, corrugated iron roofs, transparent windows where you see the furniture through, with landscape, garden furniture, trees, people and a car etc. that takes me about 6 minutes in presentation mode, resolution 2520x1575. I save that as a Bitmap, the size is about 12Mb and a TIF which is about 6Mb the quality is superb.

A project with 45 houses, solar panels on the roofs, landscape (but no textures there) with trees, roads, walkways, cars etc. takes me 3 minutes in presentation mode 1680x1050 resolution.

But I don’t run a virus scan at the same time nor any other jobs, just the rendering.

Give it a try with more memory but I don’t know how well the AMD CPU plays with that sort of a task. AC 2009 uses both cores if you use a CORE Duo for rendering. I’m using a Notebook with a T7500 (2x2.2GHZ) and 4GB Ram. But mind that clock speed is only a factor to compare CPUs when they sport the same architecture. A P4 2.7 GHZ CPU is extremely slow compared to the above mentioned. We have a machine with a P4 3.4GHZ CPU that we compared to the modern stuff just for fun – it needs about 10 times as long for a given rendering – imagine!

[Bill Tillman]

Okay, I'm going out to buy more memory. Sheesh and to think that my first Apple IIe computer ran with only 64K of RAM. But that was back in 1984. I also have another AMD Opteron with dual core CPU but that machine is running FreeBSD for the moment. I don't think the video card in it is worth much either as this machine was bought from Dell to act as a file server but I could build Windows XP on it and run AutoCAD just for grins.

 

I'm curious about how you set the resolution to 2520x1575. Do you do that under "Specify Output Settings" in the Advanced Render Menu? And if so, are there any monitors that can actually display that depth of resolution?

[David Bethel]

Bill,

 

You can take a look here for some tips.

 

http://www.cadtutor.net/forum/showthread.php?t=4318&highlight=render

 

Hardware is very important but the setup can even be more. -David

[JD Mather]

... with 896M of RAM is not exactly a slouch.

 

Actually these days it is a slouch. Don't think I've seen a new computer sold with less than 2Gig for some time. See the minimum systems requirement for r2009.

http://autodesk.blogs.com/between_the_lines/2008/02/autocad-2009-sy.html

[Cadfisch]

To set an individual resolution you open (I’m translating this, so it might look slightly different in English) “advanced render settings” – “Format” – a window “Output format” opens there you can enter your values. The main reason why I often use a higher resolution is that it allows you to only select parts of the image in Photoshop for further editing without losing quality. Also for large presentation prints it is an advantage. On a smaller screen it doesn’t seem to make a difference quality wise, but I’m not sure.

[MaxwellEdison]

Hardware issues aside, and focusing on the actual rendering, Your landscape looks rather bleak. The gazebo is modelled very well it appears, but it's just kind of sitting there. Look into getting some shrubs/bushes/flowers to surround it and make it feel more a part of a scene. Also, try moving the camera in a little closer. Right now the gazebo is taking up less than half of the picture so your eyes search the empty areas around it rather than focussing on the details of your model. My last suggestion would be to change your sky, with the bright lighting on a low angle and cloudy sky, it looks as if a late afternoon thunderstorm is about to roll in, making the open gazebo look a little less inviting. a patio set or just some chairs would also help with creating that inviting cozy feeling.

 

I hope this hasn't come across too harshly, as I do like the model, it's apparent you've put some sweat into the details. I just don't think the scene is expressing that.

[Bill Tillman]

No offense taken my friend. I too am looking for a way to make it more inviting. My age old block is that I've always been able to draw buildings and houses, things with straight lines and measureable angles. But when it comes to living things, I'm not that good. And just to put it into scale, this gazebo is 32 in diameter at the base. Not exactly a standard backyard fixture, more of a public park size.

 

I guess I could use some templates for trees and bushes, but I need to really work on the sky first. This rendering was done with the sky+illumination setting on but as you say it still looks like a cloudy day. That kind of kills the affect of the shadows. Would increasing the intensity of the sun do it or should I add some lights. I've tried adding lights but I'm finding that this is an art in itself. I'm still learning how this works.

[Cad64]

I was wondering if anyone could advise me on how to acheive finer graphics with this, like ray tracing, or filter type, etc... which works best in your experiences. I'd like to make the image a little brighter. I don't mind waiting all night for a render to complete if it helps acheive a realistic image that makes the clients go "oooh, aaaaah, I want to buy one of those."

 

You should read up on, and practice with, the Indirect Illumination settings. Global Illumination and Final Gather is where all the magic happens. Utilizing these options will make your renders look much better, but will also drive up render times significantly. You just have to experiment and find that fine line between quality and speed.

 

The filter types are listed in order of their quality. Box is the lowest quality filter and really shouldn't be used for anything other than quick test renders. Lanczos is the highest quality filter, but it really slows down render times. I generally use Gauss or Mitchell, depending on the job.

 

Samples play a big part in render quality also. Higher samples will give you better looking renders, but also drive up render times. I generally render with Min Samples set to 4 and Max Samples set to 16.

 

As for lighting, you should read up on the 3-point lighting technique. It's a pretty standard way of lighting your scenes and gives very nice results. There are dozens of 3DS Max tutorials online covering lighting and rendering techniques, but Autocad tutorials seem to be non-existant. So you just have to read what they have to say and then apply the same techniques to Autocad.

[Bill Tillman]

I'm not sure what this is but I think I've read something about it before. I have added some materials to the shingles on this Gazebo and it looks ok, but there is something wrong with the pattern on some of the other planes of the roof. What does one need to do to get the pattern to be consistent on all the roof sections. One area of the roof looks good, but then one of them looks like an egg crate with convex surfaces.

[Cad64]

Try experimenting with the SETUV command. You may be defaulting to Plannar mode. Try setting it to Box and see if there's any improvement.

 

The floor of the gazebo looks very shiny and reflective. Is that the look you're going for?

[Bill Tillman]

I'm referring to just the shingle materials. The decking on the floor was just a test I did and you're right it looks too shiny for this application.

 

I found this really great looking pattern for wood shake shingles and applied it. It did not turn out as hi-res as I thought it would but it's ok. The problem is that on one section of the roof (the one on the right in this view) it looks great with the pattern running up and down the length of the shingles. But then on any of the adjacent sections (the one on the left) the pattern runs at an angle to the shape of the shingle which gives it a shape like an egg or convex surface. It makes for a rather unique texture and is not bad actually, but it's not what I'm after.

 

I'm looking into the setuv command now. Thanks.

[Cadfisch]

If your roof is one solid, the orientation of the material won’t follow the different faces.

There might be other solutions but slicing the roof, applying the material to the sections and adjust the orientation with the “planar mapping” command works fine.

[Bill Tillman]

No, the roof is made from eight different panels which I painstakingly constructed using slice and then mirroring them where I could. The shingles were even more drudgery but again these are all separate shingles aligned on the plane of the roof they are attached to.

 

Now the worse news of all. As per the recommendations from others I spent $90 on 2GB more of memory. It arrived today and I installed it. The computer acknowledged that I now have 2.87GB of RAM. But the render still took in excess of 20 minutes to complete. With only 896 MB of RAM it was taking about the same time.

[Cad64]

Can you upload the file to a file sharing service? I would like to render it on my machine and see how long it takes. I don't think it should take more than 5 minutes. Even on high settings.

 

One thing that could be causing the slow down is the fact that you are modeling everything, including shingles, which I was not aware of before. You have to always remember that the more geometry you have in your scene, the longer your render times will be. You should always try to use materials whenever possible and bump maps to bring out the detail instead of actually modeling everything. You could also use opacity maps for your lattice work. That would also help cut down your render time.

[Cadfisch]

Cad64 you are right of course regarding modelling everything. But the building I mentioned above sports about 1000 timber panels, dozens of steel profiles, about 200 timber chevrons, about 150 timber beams, windows, glass etc. and on top of that chairs, tables, settees etc. all modelled (35 different materials and textures), and it still takes less than 6 minutes to render (1680x1050) in presentation mode.

Sorry Bill, to hear it wasn’t the RAM (alone) it seems to be the CPU then. Are you sure there is nothing in the background using up your recourses? But your money is not lost, believe me AC2009 doesn’t run properly with less than 2GB.

[Bill Tillman]

The memory purchase is not a loss at all. The computer is certainly doing some other things much zippier than it was. ACAD loaded the drawing I'm working on in a flash. That's definitely quicker than it was doing this morning.

 

The other thing I noticed was that this time the shingles came out looking much nicer than before. I used the same clip art that I found, but this time I edited in in Paint Shop Pro and then saved it as a jpeg file. This time the render took 24 minutes but the issue with the pattern of the shingles running in the correct orientation seems to have been fixed. Either it was the memory or the way I saved it using PSP. Yesterday all I had to work with was MS Paint.

 

I have nothing else running on this machine during the render there is no virus protection program. It runs Windows XP Media Edition with SP3.

 

This machine has an AMD Athlon 64 4000+ 2.41 GHz with 2.87 GB of RAM. It's not a dual core though. Sometime in the next few months I plan to upgrade and I'll splurge on Xeon Quad Core with 8 GB RAM or something.

[spittle]

I use mental ray to as my renderer and to speed this up you need more processor power, as far as I can see the amount of RAM you have really only decides whether or not the scene will render or not (i.e. crash) but the purchase was definately a neccesity.

 

I don't know about scan line renderers but with mental ray, the number of cores also affects the speed, at work I have 8x 2.66GHz cores which is a shed load better than the 2x 2.4GHz cores I have at home.

 

I think for your scene though you need to experiment with your render settings as this should not take too long. Have you got the option to insert a Skylight? Inserting one in 3DS Max is the starting point to getting natural looking shadows and a step towards reallism.

[Bill Tillman]

I re-ran the render this morning and following Cad64's advice I turned off the sky. The render took less than 5 minutes but of course with a black background it looks less than appealing. So I'm about to re-run it using a background.

 

I'm still new to most of this. Is MENTAL RAY another software package? And I do not have any access to 3DSMAX so working in that environment is not possible for now.

 

There's no doubt that what I thought was an adequate machine is obviously not adequate for this kind of 3D work. Preparing the drawing is no problem and making renders in low res 600x480 settings is a snap. Going to the hi-res stuff works, it just takes a long time. Another render I let run last night before hitting the hay was a detailed close up of some timber connections on another gazebo. I noticed this morning the render looked great, lots of detail and shadows and lighting were spot on, but the render took almost 47 minutes to complete.