Planting Geometry: RPC and Solids

There are currently two methods of modeling and showing Planting families within Revit: RPC and solid geometry. The RPC (Rich Photo-realistic Content) trees are represented by two intersecting planes of a tree in elevation.


Graphically, they usually appear as shown above, but they will render out as a photo-realistic tree (below).


RPC trees look a little better, in my opinion, but they have a few drawbacks. Mainly they are not solid, 3d geometry and so are not suited for clash detection. So while solid trees may be a bit simplistic in appearance they are essentially more functional.

Here are a few examples I have seen recently of solid trees…

Bond Bryan Architects

RCH Studios

Chris Smeaton (formerly at Colour UDL, now at KEO International)

Now, I understand the need to have a solid, 3D tree, but graphically they often make me cringe. And though it is important for a BIM model to have good information, those models are also frequently used for renderings.

So why not have both? By combining both RPC and solids into a single Planting family you can have the benefits of both. In fact, I think having the RPC outline as a reference results in a nicer solid tree. Here is a single family, with 15 different types. The above trees are the same tree, just in solid form.

family set

The solid geometry is a nested Planting family, with a variety of 6 different Form Types forming the canopy.

family  family_parameters

The solid geometry is a revolve created mostly from splines so that it can scale correctly for both Height and Width. The Canopy Ratio controls the height of the canopy and trunk (should be set between 0 and 1). The visibility of the RPC or solid is an instance parameters, but it could just as easily be controlled via Subcategories or a Detail Level Visibility Setting.

If you want to check it out, here is the RPC and Solid Planting Family.



15 thoughts on “Planting Geometry: RPC and Solids

  1. I’ve been meaning to do the same thing – you’ve saved me a job. The Canopy Ratio seems to have a practical limit of about 0.7 otherwise the trunk gets distorted. Are the two separate revolves (top and bottom of canopy) necessary? I’m not keen on the line they create between them… Subcategories are definitely the way to control visibility, then it can be built into your View Templates.

    • I didn’t test out the trunk much, but I’m sure you could adjust the revolve to make it more flexible. As for the canopy, it is 1 revolve, but with 2 splines. The line appears at the endpoint where the two splines meet. Breaking it into 2 splines allows you to tie it down to both width and height. I assumed that the solids aren’t really there for the graphics anyways, so the line wouldn’t be a big deal.

      • Solids are there for graphics in 99% of our drawings. Plans, sections and elevations are always shaded views. Most 3D views we’d share over the course of a job would just be shaded with shadows too. We almost never render – it’s too slow and time consuming.

        Example image:

      • We don’t use RPC because we didn’t have a family that worked in both 3D shaded views (RPC doesn’t look good) as well as 2D shaded views, plus you also get another unwanted line in elevations – the vertical one in the RPC. It looks like your combined family might work for both though.

      • Yeah, I think the poor performance of RPC in shaded views has lead to me preferring consistent colors. Though I also don’t like what Topo does in shaded views either.

    • I have been trying to control the visibility via subcategories but have had no luck.
      Have you or anyone else had this same problem?

      • Hi Nick, thanks for the comment. I have seen this and I have not found a way around it. It seems like the RPC element is impervious to subcats. Since Archvision owns RPC, I would recommend contacting them and asking them about it. In the meantime, you could use Visibility Detail Levels.

        Chris- have you been able to implement subcats for RPCs?

      • A possible solution to have view spesific visibility settings of PCP could be to make the family shared and nest it into a “empty” container family together with another shared family with solid representation. A view filter can then be applied to the view to hide one of the shared nested families within the container family. For example, filter by family name or a yes/no-parameter called “Show only in rendering views”.

    • You need to start the family from an existing RPC family. I believe there is a Planting RPC family included in the Autodesk library and it should be loaded into the default Architectural template.

      • Thanks, and I managed to find that right after I posted! It was a facepalm moment.
        I have since been making custom RPC families for our Landscape team (and their template) before they even learn the program, and I am wondering if you have ever used Archvision for creating custom RPCs. If not, do you know of any other way to create a .rpc file that can load into Revit? I have been using images of planting that is indigenous to our region (none of which really show up in the out-of-the-box RPC families in the Render appearance parameters), and using Archvision to convert them to a .rpc file. The problem with this is that if you don’t have a license, a watermark will print all over your families. I have a license, but this means that anyone else who prints the drawings will print it with a watermark. So, do you know of ANY other program that converts a .png or .jpeg to a usable .rpc?

  2. Hi Melonie, that is an excellent question. I have not used Archvision’s RPC Creator, but from what I know it is the only program that creates RPC. In fact, from what I understand, Archvision created the RPC (and thus owns it), so I don’t think there is any other option. This is somewhat unfortunate and it makes using RPC for plants rather less appealing.

    I would be interested to hear if you find any other solutions, though. Good luck!

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