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Commercial Scale BIM into Unity 3D

Discussion in 'External Tools' started by Siusega, Apr 7, 2015.

  1. Siusega


    Mar 5, 2013
    Does anyone have some tips/research/reading materials on methods of combining massive Revit models from Revit to Unity 3D on a commercial scale?. That is to include 100% detail - pipes, ducts, walls, floor, Structure, fittings etc.. into a Unity walkthrough.

    I have been doing for some time now but it takes a very large amount of time optimizing and combining mesh material within 3DS Max - especially with Revit meshes from MEP packages i.e. the most polygon dense models.

    I have simulated a few mega models but none with 100% detail - I have always had to ignore smaller detail (with high polygon count) as a result of Unity crashing at that stage from excess content.

    So I wanted to start a discussion on - what are the best methods for porting & simulating 100% detail for commercial scale mega 3D models into Unity from an AEC based application - such as a Revit.
  2. frankrs


    Aug 29, 2009
    The closest I've come to that is running the fbx through 3dsmax and using some maxscripts to seperate meshes by material names and then exporting to Unity. Still very laggy though, as you're talking millions of verts.
  3. mgear


    Aug 3, 2010
    Deep Exploration or similar for cleaning / optimizing up the model (removing duplicate materials, faces, hiding internal objects etc)
    3ds max: ProOptimizer, Collapse objects, custom scripts to select small objects (to hide), export multiple smaller files, (so the import wont take forever, especially when changing import settings and then it re-imports..

    Cylinders/Pipes usually break when polygons are reduced though..
    sirxeno and theANMATOR2b like this.
  4. LaneFox


    Jun 29, 2011
    There is no good workflow at this time. You basically just have to run the models through Max and export as fbx (or a Unity supported) format. Blanket style optimizations are the only feasible types and you can't really intend to continue updating the Unity model with the current designer model on a regular basis (ie, weekly) because its simply too much to do and inconsistent.

    You can run into a ton of issues with the models but its depending on the original software. For instance PDMS is database driven and their exporter to dxf files makes absolute garbage with missing faces, duplicated verts and a slew of other problems... whereas pushing from Autocad is nearly problem free most of the time aside from some weirdness with Block References.

    64k limit on meshes is another issue, but this also depends on how your models are grouped and is often easy to overcome.

    Overall I strip out all of the greebles like bolts, nuts, anything too small to notice, most 3d text, etc... and also reduce curved shape accuracy until I get about 12 - 18 sides for circular objects and don't lose too much in the elbow fitting shapes.

    It's really just trial and error, try on some crazy equipment and get some ideas, then repeat on more models.
  5. theANMATOR2b


    Jul 12, 2014
    Completely agree with mgear and LaneFox.

    What is the need for 100% detail?

    I just worked with a "part" that could of been completed in about 20k polys with very nice/acceptable resolution but without mesh editing the imported model was nearly 3 million polygons. Obviously there is wasted resources used by such high resolution models.
    The best optimizer I've ever used (as a trial) was deep exploration. But I experienced varying results when dealing with different types of models, so tweaks to the settings was always required. This was around 10 years ago so modern updates may have improved greatly.
  6. Siusega


    Mar 5, 2013
    @theANMATOR2b - I work for a contractor company and in our role we evaluate every bit of detail in 3D models before construction begins- especially the small stuff in Architectural models that need specialised design. So having a walkthrough showing that Level of Detail is a big plus for the sub contractors that do not have access to 3D modelling packages. Especially if its free using a web player (although now we have cloud simulators).

    We generally use Autodesk Navisworks/TeklaBIMsight/Solibri for these simulations (as those are built for it) but simulations that need more flair & special effects with animated characters - we would prefer to use Unity 3D. Except the 3D models from Revit (or other applications) are severely stripped out - for performance.

    I guess trial and error will be the way to build the simulations for now until hopefully the engine develops further for heavy AEC BIM Models.