revit2008 model rendered with Vray in max8

[steedlei]

Hi all, I woder if anyone hiving the same problem as I just encountered for rendering revit model using Vray. I exported my revit 2008 model into dwg, then use MAX8 link manager to link the dwg then convert all material into vray material. Basically there are 2 problems: 1, It takes nearly twice as long as the time needed to render if the model is built by max itself rather than linked from revit. 2, the quality of rendering is slightly off, looks bit more carton like (We have done quie a lot renderings in Vray before so we can tell the quality rendered on revit model is not as good). This is the first time we use revit modle to render photo-realistic rendering and animation, we used to create all models in max. Anyone has a clue of problems I mentioned? Maybe I must use max9 instead of max 8 to render?Thanks in advance for any help!

[dhurtubise]

One thing that you need to manage is create yourself a good export file for Max from Revit.
Also make sure you only load the data you really need.
It will affect the rendering time because REvit creates a lot more geometry them Max native format. But if you look at the overall process you are still gaining a lot of time.
Quality shouldnt be an issue

[Andre Baros]

The time issues is probably related to all the extra faces which Revit is giving you. It helps a lot to join elements together in Revit before exporting them so that it doesn't export many of the hidden faces (like where the bottom of the wall hits the floor, etc)

I can't explain the "cartoon" look, but that must be a v-ray issues... unless you usually bevel and champer all the corners on your max models and just have all the square corners of your Revit model.

[rmejia]

Basically there are 2 problems: 1, It takes nearly twice as long as the time needed to render if the model is built by max itself rather than linked from revit. 2, the quality of rendering is slightly off, looks bit more carton like (We have done quie a lot renderings in Vray before so we can tell the quality rendered on revit model is not as good).

It sounds like a render settings problem, nothing to do with Revit and the exported model. Do you apply materials you have created in Max to the model once imported? The materials that come from Revit are not good materials to use, they all have to be substituted in Max if you want to have good materials in the model. The render time comes down to the render settings and the materials used. I have not experienced any difference from models created in Revit and exported vs models created in Viz/Max, they both behave the same.

[steedlei]

Thanks for the help. One thing we just find is that "export as ACIS solid" option can reduce the verall number of vertex of entire model by 60% comparing with "export as polymesh" option. This may cause some difference in rendering time too. I dont know generally which option you choose when exporting to dwg/max?

[chris.hitchcock.nz]

I have only ever used export as a mesh, it seems to work absolutely fine, (used to work in max 8, now in version 9) if you want to get into you can go through and set up all your export settings so things go to layers you want them too, or not export at all, things like door architraves, etc arent that useful for big external renders. I guess it all depends on how much detail you want, i perfer having all the pieces there, and modeled in Revit to a reasonable detail.
Also most of the time i export as a 2004.dwg as initially had problems with 2007.dwgs (they seem to have sorted it in max, but i still do it!),
As for the quality looking like a cartoon output, that sounds odd never have encountered that before.

Good luck, i find revit pretty useful for my MAX work.

chris.

[rmejia]

Thanks for the help. One thing we just find is that "export as ACIS solid" option can reduce the verall number of vertex of entire model by 60% comparing with "export as polymesh" option. This may cause some difference in rendering time too. I dont know generally which option you choose when exporting to dwg/max?

I export as polymesh, the ACIS solid option has never worked well for me, if I remember right the main problem was that the model would loose it's material assignments. Max 2008 seems to have improvements on exporting from Revit to Max in ACIS solids, I hope the materials stick in Max 2008!

[dhurtubise]

What do you mean by material dont stick ? Are you using the Revit material in max ????

[dellis]

It should work fine. I just did a quick test...thanks Daniel...and everything worked fine with the materials. My workflow was as follows:

-File link Revit drawing.
-Select the object and use the get material button to put into a material slot.
-Once the materials are in a material slot i convert them to a vray material.
-Then if/when there are changes to the design in Revit you have to make sure that you have the show reload option box checked.
-Then once you click the reload button you will get the "File Link Settings" dialogue, in the advanced tab make sure that "Use scene material definitions" and "Use scene material assignments on Reload" are both checked on.

That should work for adding objects as well as maintaining materials for changed objects.

[rmejia]

What do you mean by material dont stick ? Are you using the Revit material in max ????

In Revit I use the Paint tool to apply materials to the faces of the model. For example I paint the building exterior walls with a material called "Paint - Brown - Light" which is just a color in Revit, in Viz I then use the select material tool (little eyedropper) and place the material in the material editor, I then use the select all instances button to select all the elements with the "Paint - Brown - Light" material applied and replace them with the "Paint - Brown - Light" VRay material I have created in Viz. The materials also have to have the same name in both programs, or when the file link is relinked, the materials applied in Viz are lost.

The times I used an ACIS model in Viz, the elements would come in all yellow or blue, with no "Paint - Brown - Light" or any other material applied to them. They lost that information, so I could not easily replace the materials in Viz.