Raytrace Takes Tremendous Time - What do Others Do?

[artitech]

Yesterday we needed to put out some interior and exterior renderings expediently for a presentation... should have known better...

I did an interior view of a lobby at 200 dpi and after 2 hours it was only at 44 percent complete. I am running a Pentium 4, 3 Ghz w/ 1.5 GB Ram.

Here's my concern....
I needed to get other work done in Revit, but while my computer sat busy rendering the scene, I sat idle - patiently waiting to get the next scene rendered with the deadline rapidly approaching .

How do others deal with the amount of time it takes to render scenes? I believe in 3D Studio there was a way to output the rendering process to other computers on a network - something like that would be ideal with Revit so that one could continue working on their model and subsequent scenes to be rendered.

Comments, thoughts, words of wisdom?


THX.

[cosmickingpin]

Here are some threads to help you out. What is your image size? getting the right ratio between images size and DPI is the main factor in getting reasonable results. Also for quick renderings I like to take just a screen shot, and "color" it up in photo shop by adding lighting effects, color and textures, people etc... They are quick and "expressive" and in most cases faster then accurender. Czoog has outlined a great method for separating the rendering into several step, and then combining the results in Photoshop. That can save you a lot of time.

http://forums.augi.com/showthread.php?t=16332
http://forums.augi.com/showthread.ph...ight=radiosity
http://forums.augi.com/showthread.php?t=16445


***I wish I could show you example of those Photoshop paintings but (as I was reminded in a company wide memo from our legal department yesterday) all work is to be kept confidential and all releases to be coordinated by our marketing department.***

[niki_funky]

Hi

In our company we use Revit for designing and 3d Max with Vray for rendering. You can look at some of my images. They are all rendered in 1or 2 hours. Of course it took some time to texture the model. And of course you must have some knowledges on Max and Vray.

best regards
niki

[SkiSouth]

Rendering can vary greatly with each scene, machine and software chosen. Size of the image can also take its toll. A 3x5" render at 400 dpi, could be faster than a 150 dpi at 17x21". If possible, use a smaller image at a higher resolution, and up the image size post render with something like photoshop. Also, Accurender recognizes multiple processors. If you MUST work while rendering on the machine, request a new dual processor machine . It will allow you to be a little more flexible with your time. Unless you are running something like a PURE card, then almost any rendering software will consume processing time. Radiosity is also a time hog in Accurender (as well a memory consumer). I'm sure you've read about the hours of render time involved in running Maxwell (and I use a quad processor machine). It varies. For me, I have found that a good 300/480 render will take about 20 to 40 minutes in revit/accurender. It can take longer though if I''m processing RPC's, trees, reflections etc. Number of faces of objects, materials like glass, reflections all take their toll.

Unfortunately, without seeing how you've set the scene, along with the scene, I can't be more specific. You can post the file if you wish, and have a "comparison" render times performed by willing users on various types of machines possibly.

Render farms are available on line. Unfortunately, as you have pointed out, the software would have to have the capacity for this, AND you'd have to have a license for that number of processors. 3ds MAX is not an issue with render farms, but Maxwell, Vray, etc. all have a specifed limit on number of machines allowed. If you're finding this happening more and more, but you're satisfied with the Accurender solutions, then I'd say a new monster dual processor box knocked out with memory would be your route.

[Max Lloyd]

You can always open up another session of revit and set up your scene whilst waiting for the other session to render.

[artitech]

You can always open up another session of revit and set up your scene whilst waiting for the other session to render.

I though this was a no-no with Revit, performance wise..? Also, another piece of the puzzle - it's a workset project, can I open two sessions of the same workset?

All good input here, it will take me a while to get through it all.

One thing though, perhaps I'll get over it - but I like to utilize "one" program as much as possible so I prefer not to go outside of Revit (at this time) to achieve my final renderings (other than perhaps Photoshop). A bit naive perhaps?

[cosmickingpin]

Unless you have a dual processor I wouldn't recommend it at all. With a dual processor I find the effect on rendering output negligible and perhaps more than offset by the time I save by remaining productive.

Utilitzing single software, is that like a religious thing? I am not sure where that coomes from, but use whatever tools are needed I always say.

I though this was a no-no with Revit, performance wise..? Also, another piece of the puzzle - it's a workset project, can I open two sessions of the same workset?

All good input here, it will take me a while to get through it all.

One thing though, perhaps I'll get over it - but I like to utilize "one" program as much as possible so I prefer not to go outside of Revit (at this time) to achieve my final renderings (other than perhaps Photoshop). A bit naive perhaps?

[sbrown]

we have graphics stations that we use for rendering if we need to keep working. With worksets its no problem, just open your project get all your settings right, when your ready to render, STC relinguish all, then Raytrace. Then you can open your file on another machine and keep going. Typically someone in the office is gone to a meeting or something so you can render on their machine.

The biggest thing to improve rendering, is size(small as you can get away with for what your printings, you very rarely need to use the best setting at 300 dpi. Usually better at 150 is sufficent. 2 trees are killer, each leaf has to cast a shadow. Render these sep. then paste in in photo shop(they maybe able to be rendered at a lower res too.

Lights also take a longer time to render.
Utilize the view culling check box and back face option.

[hand471037]

Here's my concern....
I needed to get other work done in Revit, but while my computer sat busy rendering the scene, I sat idle - patiently waiting to get the next scene rendered with the deadline rapidly approaching

While being careful about your render setups and such will make them go faster, they will still take a long time, esp. when big/complex. So there's three things you can do that I know of:

A. Get the biggest computer you can and run more than one session of Revit. Not the best solution, for the computer that can do this is expensive and running more than one session on a very large project slows down both what you're currently doing and what's working in the background. But it can work, and it works with Worksets as long as you change your workset username in the second session prior to opening the project again. I do this sometimes and haven't had any issues.

B. Use something else to do the renderings. Someone already recommended Max + Vray, and there are a ton of other rendering engines out there that are more efficient (faster) and of higher quality image-wise than Accurender in Revit. Not the best either, for you've got to export the model, sever that nice bi-directional link with everything that really helps with last-minute edits, and you've got the cost and learning curve of dealing with another tool that's just as complex as Revit (and, depending on the 3D software, has a worse UI to boot). Some of these can use network rendering solutions as well to speed things up.

C. Buy a second computer. When I'm doing rendering work at a client (I'm freelancing right now) I'll set up the render on the fastest computer I can get my hands on, and then go back to my laptop and keep working. I know a few folks that do pro rendering work for Architects, and a lot of them will have multiple computers tied to the same monitor with a KVM switch, and just jump to whichever one isn't currently busy to do work while the others render away. Not the best either, for now you've got a second computer to manage, more licenses to buy, and issues of consistency with your setup. And you're still stuck with Revit's slow and 'just ok' Accurender engine.

So, 'A' sucks because you've just got one expensive computer that you're slowing down both things you're doing. 'B' sucks because you have to buy extra software and learn it, but it gets you better renderings. 'C' sucks because you have to manage another computer, but lets you stay within Revit and keep a lot of speed.

What would be best I think is some combo of B & C, but where it's built into Revit. Like a Mental Ray/Maxwell/Radiance/Vray plug-in for Revit that could also tie into some kinda render farm, so that the renders are off-loaded and not running on your local machine. This is how the 'big boys' do it, ala Catia or Max, where if you've got the hardware (like a RenderDrive or renderfarm setup) you can just submit the job to it and keep working locally while the job gets done remotely...

[Andre Baros]

One additional note is to manage your expectations and your clients. With a tight deadline, you may only be able to do a really good shaded view, tweaked in Photoshop, or even a wireframe view tweaked in Illustrator (my new favorite). If you need a nice rendering, than you have to ask for the time or lower everyones expectations. It is possible for it to go smooth and fast, but it's very very rare.

Something else that I've been using successfully lately is hidden line animations. 3 minutes of hidden line animation renders from Revit in less than 10 minutes and can show a whole lot more than a really good still (if your talking space not material). Beware of hard drive space and compression time. I render out to frames first so that I have options in post, but that means that I have another hour after the frames are made to make adjustments, render to Quicktime and compress the raw frames.

I favor an all-or-nothing approach. I either take the time to "Maxwell it" (using a dedicated render machine) or I rely on wire-frames tweaked in some way.