Importing from Revit (and using Materials)

[jdshanks]

Basically we want to use Viz for the network rendering. We have 40 computers set up and working great. But there have been several issues when importing a file from Revit.

a) It seems that phasing has to be deleted for a model to export with split faces and everything. Can anyone confirm or deny this?

b) The main problem is with materials, in that they don't always pull forward to Viz. Some do, some don't. Those that do, only the bitmap itself comes forward, but if a color correction has been applied in AccuRender [from Revit,] the new color does not show up in the rendering in Viz.

The models look fine when rendered in Revit, it just takes forever. We really want to take that, throw it into Viz with better lighting and bump mapping, and be able to render it in an hour (not 2 days). Any help would be greatly appreciated.

[brett05]

I am by no means an expert on this, but having just attempted what you are trying, I have found the exact same results.
I ended up abandoning Accurender because of poor results (maybe pilot error) and applying all of my materials in VIZ using architectural materials. I used a daylight system to create the lighting for my exterior rendering. I found that I could get really fast radiosity processing (a few seconds) and renders (10seconds) by using the following settings for test renders(off the top of my head)-->
Radiosity
- Initial quality 40%
- no refine iterations
- no global subdivision
- re-use direct illumination from radiosity solution
Environment and Effects
- Logarithmic exposure
- Exterior daylight
Render at 1000x500

For Final Rendering
Radiosity
- Initial quality 90%
- 10 refine iterations
- global subdivision @ 500mm min & max
- render direct illumination with regather direct illumination selected @ default values
Render at 3000x1500

For final rendering, radiosity processing took about 30-40minutes and rendering took 90 minutes.

HTH
Brett

[jwilhelm]

Accurender is a multi threaded application, I would think 40 computers would speed even accurender up

[jcdecastro]

If you are interested in speed (along with quality ofcourse), you should look into using Vray. It s a rendering plugin for Max/VIZ. http://www.chaosgroup.com/software/vray/ .To get the speed you have to sacrifice your materials a bit though....you have to convert all or almost all materials to Vray materials, especially glass and metals, or anything with a reflection. Once you convert, speed is at your finger tips.

I use revit to model, export dwg, file link to autodesk VIZ, convert materials, Vray for rendering. Test renders around 1-2 minutes. Most final renderings are around 5 minutes. 20 minutes is an absolute max. And this is with Gobal Illumination (Radiosity) included. You can save the Global Illumination similarly to how its done in VIZ. Duo Core 3.4, 3.5 Gig Ram. I intend to set up a renderfarm in the office but havent gotten around to it, after that I might blink and the rendering might be on the screen.

I know i havent answered your questions but, if you are rendering for 2 days, I figure you can get around those problems with the time you will gain.

[angelo]

We haven't used VIZ and Revit in a full production environment yet, but from my experiments, I don't think you can rely on materials coming through from Revit. You are exporting the file from Revit, so beyond the intelligence of knowing what each object is, it's a stretch to think materials are going to be there.

However, once you map materials to a linked dwg from Revit, it's pretty good a updating the model (you just overwrite the file with the same name). Even if you extend a wall, the uv mapping figures it out. Set up some selection filters and just re-apply stuff each time the model is re-linked (to get any new objects-i.e. additional glazing).

The architectural materials in VIZ work nicely with the radiosity, but once you try and build ones yourself, or standard materials, things get wacky very quickly. Vray and Maxwell are two third party renderers that have huge potential in getting very good looking images without a major amount of tweaking.

Good luck!
Angelo