FBX or DWG export for max import?

[Brian Cassil]

I know there are bits of info available for this in several other threads but I thought it would be valuable to consolidate the info into one thread since this seems to be a topic that several people are actively engaged in evaluating... at least I am. I will list what I know to be the advantages and disadvantages of each file format. I am hoping that people will be able to contribute to this so we can have a good collective understanding of what will work best for differing situations. I have added any mitigating factors to the disadvantages in blue.

 

FBX -

 

Advantages:

 

1. no block headers

2. mental ray materials applied in revit appear in max

 

Disadvantages:

 

1. everything is on layer 0

if materials are applied in revit, those can be used to select and assign materials in max.

2. the max fbx import options do not have any filters for geometry (everthing in the fbx file has to be imported)

a view template can be created in revit that would filter out the unneeded objects.

3. triangulated meshes

4. no file linking

 

 

DWG

 

Advantages:

 

1. clean non-triangulated meshes

2. layers

3. more geometry filters in max dwg import options (selected layers can be excluded/included)

4. file linking

 

Disadvantages:

 

1. no materials

2. lots of block headers

Edited August 22, 2008 by Brian Cassil

[Brian Cassil]

As I typed the above out I realized that the one list is a perfect inverse of the other... duh!

 

Anyway, a couple of comments and questions I have. In my experience the block headers is a major problem with the dwg option. They seem to enflate the file size to 2-3 times what it would be otherwise. Anyone else notice this? Also, what is the advantage of file linking a dwg that was exported from revit? Once revit exports anything (even fbx for that matter) the continuous update from revit is broken... isn't it? The only real advantage for file linking that I could see would be to link the revit file itself. Lastly, I have not looked at the mental ray materials in revit at all yet. How useable for rendering are they? Please feel free to comment and I will keep the above advantage/disadvantage list updated as well as post any mitigating factors.

[Chad Warner]

From my personall standpoint, I'm much quicker in AutoCad than Revit, so any changes that have to be made to the model (and there are always changes) I like to be able to do in AutoCad, so my preferred method is Revit-->Acad-->Max.

[Brian Cassil]

From my personall standpoint, I'm much quicker in AutoCad than Revit, so any changes that have to be made to the model (and there are always changes) I like to be able to do in AutoCad, so my preferred method is Revit-->Acad-->Max.

 

This is perhaps where a different solution for a different situation is worth considering. Since I work in an architecture firm I am looking for a solution where the revit file can be updated as quickly as possible in the max scene. I am working very closely with our reviteers (they actually call themselves that) so that there would be as little as possible that we would have to change in the model to prepare it for max renderings.

 

For rendering studios who get an exported file and have minimal contact with those who have generated the fbx or dwg I could totally understand why a different aproach could be taken. There would probably be fewer updates and therefore some tinkering with the model would not be so much of an inconvienance to do once or twice. To make those modeling corrections for 10-15 rendered updates (not uncommon with many of the projects we do) would be a major problem.

[Stan Zaslavsky]

i'm just going through a job where the revit architect did a very poor job of aligning windows and a few other crucial pieces of geometry - so when i exported FBX --> Max - i've got a lot more cleanup to do, plus remodelling columns and some other architectural features - i've had to virtually start all over with those in Max

 

the mental ray materials exported from Revit do come through ok - but once again they depend on the operator of Revit - which in this case hasnt been the best

 

 

so all in all i'm with Chad on this one - Revit - Cad - Max

 

cheers,

[Brian Cassil]

Thanks for the input Stan. Can you tell me if you are an in house visualization artist for an architecture firm or are you a freelance artist?

 

nm, I just noticed your website.

[Brian Cassil]

It appears that neither the dwg cleanup or the autoedges scripts have been updated for max 2009. Actually, we can't get them to work in 2008 or 2009. Has anyone had success with them in Max 2009?

[Tay othman]

See that Video...I've Liked the ACIS Solids

 

http://download.autodesk.com/us/3dsmax/siggraph2007/demos/Revit%20Interop.mp4

[Antisthenes]

i use a script that exports each layer to its own SAT (ACIS) file

[Brian Cassil]

i use a script that exports each layer to its own SAT (ACIS) file

 

Can you post what script that is and where you got it?

[Antisthenes]

sure thing. it is at home and i got it from pascall, so when i get there i will find it and post it.

[Brian Cassil]

See that Video...I've Liked the ACIS Solids

 

http://download.autodesk.com/us/3dsmax/siggraph2007/demos/Revit%20Interop.mp4

 

Interesting. I was unaware that material assignments came across with acis solids. I've done a couple of tests now and we are getting thousands of different materials. We have some duplicate materials with FBX but not nearly that many. I'm pretty sure this is something that needs to be corrected on the revit end of things. Does anyone know why so many different materials are coming in?

[Crazy Homeless Guy]

I know there are bits of info available for this in several other threads but I thought it would be valuable to consolidate the info into one thread since this seems to be a topic that several people are actively engaged in evaluating... at least I am. I will list what I know to be the advantages and disadvantages of each file format. I am hoping that people will be able to contribute to this so we can have a good collective understanding of what will work best for differing situations. I have added any mitigating factors to the disadvantages in blue.

 

FBX -

 

Advantages:

 

1. no block headers

2. mental ray materials applied in revit appear in max

 

Disadvantages:

 

1. everything is on layer 0

if materials are applied in revit, those can be used to select and assign materials in max.

2. the max fbx import options do not have any filters for geometry (everthing in the fbx file has to be imported)

a view template can be created in revit that would filter out the unneeded objects.

3. triangulated meshes

4. no file linking

 

 

DWG

 

Advantages:

 

1. clean non-triangulated meshes

2. layers

3. more geometry filters in max dwg import options (selected layers can be excluded/included)

4. file linking

 

Disadvantages:

 

1. no materials

2. lots of block headers

FBX -

 

Advantages:

 

1. no block headers

2. mental ray materials applied in revit appear in max

3. families from Revit come in as instances in Max

 

 

Disadvantages:

 

1. everything is on layer 0

if materials are applied in revit, those can be used to select and assign materials in max.

try creating a master library that has the same name as the materials you created in Revit. then use 'Update Scene Materials from Library' feature. it will automatically update all of the materials.

2. the max fbx import options do not have any filters for geometry (everthing in the fbx file has to be imported)

a view template can be created in revit that would filter out the unneeded objects.

3. triangulated meshes

4. no file linking

AutoDesk has a white paper out on how to create a poor man's FileLink with FBX. ..basically, it involves importing the file as an FBX, then Xref Objecting that scene into a new scene. as of yet, I have not fully explored this option becuase the FBX is so heavy, that it brings the system to a standstill when I try to Xref it into a new scene.

http://usa.autodesk.com/adsk/servlet/index?siteID=123112&id=10155245

[Brian Cassil]

Thanks Travis. I was actually thinking of your idea on the material naming convention thing. Except I was thinking of having corresponding named materials (xref materials if I follow the white paper that I have also read) that would already exist in the max scene and then "use scene material" could be used to automatically overide the revit materials on import. I haven't tried applying that theory yet though.

 

On another note, have you been able to use either the dwg cleanup or the autoedges scripts in Max 2009? As I think more about this I would go with DWG for now if I could just get rid of all the damn parenting and block headers.

[Stan Zaslavsky]

Hi Brian,

 

thanks for looking at my website.

 

another reason to stick with DWG - in the latest 3DATS book they discuss specifically this issue of bringing in foreign 3D modelling into MAX - their suggestion is basically same as Chad - clean up linework in CAD and model everything in Max.

 

another issue i've had was we needed to change the doors and windows in the Max file - because Revit file brought in doesnt allow for quick modification like the Max Doors/Windows can and so with all the triangulation of surfaces - positioning of doors etc was a lot of mucking about.

 

so i guess unless the Revit people know exactly what they are doing and create an absolutely clean and perfect model - then you or your Max people will have a longer time trying to fix mistakes and then get to rendering.

 

Also the materials that Revit has brought in - for every wall there are two - there is a Stud and a Exterior Render material and this too can create issues of matching multi-materials - rather than having one exterior wall material like we would in Max.

 

hope this helps,

[Brian Cassil]

OK my idea on using the "use scene material" thing isn't going to work. I guess that dialauge only pops up when merging scenes, not importing. When importing a scene with a material that has the same name it just creates a duplicate material with that name and never gives you the option to replace it with the scene material. Travis's idea of using a material library seems like a good one. I'll give that a try.

[Chad Warner]

I have the same problem as Stan....I don't work directly with the designers, so I end up having to fix things myself. A lot. I have yet to receive a revit model that goes right into Max with no cleanup first.

[Crazy Homeless Guy]

Yes, recreating the geometry in Max will provide the best results, but it also wreaks havoc on budgets and timelines. The goal of creating an efficient work flow from Revit to Max is to reduce the overall amount of work it requires to create intriguing visuals.

 

As noted earlier, a project can go through 10-15 design stages / rendering updates. And depending on the level of changes, that could mean rebuilding a large protion of the Max model every time. Doing this can be very time consuming, especially when you consider that there is an entire architectural production team cranking away on a Revit model. With an efficient workflow, you can harness what is available, and use it to your advantage.

 

I am not opposed to bringing the model in to AutoCad as a 'in between' step, but I don't really want to spend a great deal of time making changes in AutoCad. I don't want to spend a great deal of time making any changes to the model for that matter. The time spent should be on updating, and enhancing the model, not rebuilding it.

 

OK, enough of my idealism when it comes to how it should work, it is time to roll up the sleeves, and make it work.

 

Brain,

 

I have had success with the hide edges script. Simply select your entire model (important,) and run it through... Utilities > MAXScript > Run Script. It may take a little while, but it works.

 

I still haven't had a lot of time with the DWG un-parenting script.

 

One of the things I have been working with is creating a layer map out of Revit for DWG files. This map would put the different pieces of the Revit model on layer according to what material they are. In theory this should create a perfect FileLink workflow, but I haven't fully studied that part of it yet. I have spent most of my time on the DWG workflow trying to figure out how to ditch the parenting to make the model less taxing on the graphics card.

 

Anyway, I will be happy when I am able to update my Max model with the Revit model in under 30 minutes. I would consider this to be effecient.

Edited August 22, 2008 by Crazy Homeless Guy

[Crazy Homeless Guy]

Anyway, a couple of comments and questions I have. In my experience the block headers is a major problem with the dwg option. They seem to enflate the file size to 2-3 times what it would be otherwise. Anyone else notice this? Also, what is the advantage of file linking a dwg that was exported from revit?

 

I am not sure if my DWG file is 2-3 times larger than what it would be, but compared to the FBX, it is quite a bit smaller. Right now my DWG is coming in at 19.4 megs, my FBX is 82 megs.

 

With the DWG work flow, I am trying to map layers out of Revit that correspond with the materials of the building. I will then link this file into Max using FileLink. Then I will assign materials and mapping to the model.

 

If all is setup properly, the next time there is an update to the project, I will open the Revit file, load my layer map, then export to a DWG. Then I will launch the Max file, open the FileLink dialog, and tell it to update the DWG.

 

At that point, if everything is set correctly, Max will update my model per the architecutral changes. The FileLink update should keep the corresponding material and mapping assignments, meaning I don't have to spend time redoing this.

 

A couple of other things to consider. AutoDesk has implied in user meetings, and in writings they have released that there will be FBX-FileLink in future releases.

 

Another thing to look into, nPower has some special tools for importing Revit models into Max. You might be able to develop something off of that.

 

Again, the bottom line for me is about developing a workflow, not just importing models. Otherwise I might as well be pissing into the wind.

 

(Vulgar, I know. It was more of a reference to 'Badly Drawn Boy,' who I am listening to as I right this).

Edited August 23, 2008 by Crazy Homeless Guy

[sandiarch]

friends,,

still i think there are problems importing fbx format....For now i am happy importing..... Revit--->dwg---->max...(happy with layers to asign materials in max...)

but autodesk should do something so that revit->fbx-->max should have everything good.

[Antisthenes]

here is the export each layer to SAT script i mentioned

 

also i threw in another one i like that exports hidden blocks to individual files zoomed extents.

[Crazy Homeless Guy]

here is the export each layer to SAT script i mentioned

 

also i threw in another one i like that exports hidden blocks to individual files zoomed extents.

 

Hi Jonas. Thanks for posting those scripts. My Revit knowledge is not that robust. If you get a chance, can you explain the process for using a script in Revit.

 

Thanks,

Travis.

[Crazy Homeless Guy]

I don't mean to sound like a lunatic when posting to this thread, it is just out of frustration. It seems like every year new things come out that are supposed to make our life easier, but often it requires a lot of initial work in order for them to make life easier. At least in my opinion. Maybe I am trying to be a little to ideal to my situation.

[Antisthenes]

they are scripts for working with 3d DWG or native files out of Rhinoceros to get you solid NURBS geometry for Revit or other.

[Crazy Homeless Guy]

they are scripts for working with 3d DWG or native files out of Rhinoceros to get you solid NURBS geometry for Revit or other.

 

Ahh, I see. I thought they were script for getting clean SAT geometry out of Revit. My fault.