### Limiting Panel Size

Here's a fun little tip, something I gave myself a good dope slap for not figuring out earlier. Say you have a free-form surface, and you want to build it out of a paneling system. Presumably you would like to make it out of roughly similar, if not identical panels, to simplify manufacture.
Out of the box, Revit will dice up a complex surface like this, with surface divided into a "max 10'x10'" grid.
Notice that the panels have an enormous variation in size. This is because Revit uses UV coordinates to divide the faces and has to make a single measurement in each direction along the surface for the "Max 10'" measurement. The rest of the cells just take this initial spacing and run with it. For this surface, with a "max 10' division", I have a resulting grid system where the smallest cells are about 9.5' and the largest are over 30'. That's a big variation, and is a result of the single measurement of the U and V direction of the surface.

What to do? Most really irregular surfaces cannot be rationalized down into identical panel systems, but you can limit ranges of variation. In general, I am going to try and make Revit make more U and V measurements.

To start, I make a simple panel and load it into another curtain panel.

The host curtain panel system gets a divided surface. The divided surface is set to have a maximum division of 10'x10' with my base panel loaded into it.

This is the key to the optimization. Load this nested panel system into the free-form curvature system. The result is this:

So now after the initial measurement of Max 10' that Revit made on the whole surface, each nominally 10' or less cell is evaluated again to make sure it does not exceed 10'. The result is that I have a surface that is divided by panels that range from around 5.5' (if the host cell is slightly larger than 10') to 10' (if the host cell is exactly 10'). Perhaps this is not "optimized", but you do have more control over variation. I also think it looks way cooler, if not cheaper.

1. hi, this is a stupid/semi-unrelated question. I've just started playing around with revit for form making and havent been able to make a divided surface, like the one you have in your third thumbnail. I can make that shape, the issue is when I go to apply a divided surface its more of a cookie-cutter like cut out of a rigid grid. that is, the divided surface doesnt follw the deformation of the shape (aka same number of Us and Vs from top to bottom and side to side). Any suggestions? thanks!

2. Hi Alex,
Sounds like your shape is actually flat, rather than curved in 3 dimensions. Planar faces will always divide in regularly spaced rigid grids. If this isn't the case, please send me the file so I can take a look.
thanks!

3. thank you, I think I understand that issue now

I hope you dont mind me using this as a discussion for this type of modeling in revit but I have another question: Lets say I have a surface thats a loft of irregular splines. The divided surface I have is 10ish U curves running in the cross-section direction, and one in the V curve in the perpendicular. I build a curtain panel of a 2'x2' crossection that I sweep along one of the U pattern-edges. But when I bring it into the project and apply to the irregularly shaped divided surface it doesn't follow the splines, it just shoots straight across as if its trying to facet. is there a way around this? basically a curtain mullion that follows organically along a spline?

sorry if this is confusing!

4. Well, the short answer is that panels and patterns in the divided surface just connect points to points. This is different from the "unpatterned" divided surface which actually still describes the curvature between points.

5. im assuming by "unpatterned" you're referring to the "no-pattern" type option for a divided surface? how would I go about applying a form to flow across the splines created by this 'no-patterned' surface since there's not a 'no-patterned' type in curtain panel patterned based family creator?

6. Alex,
Can you send me an image of what you are trying to do? I've seen some other questions in the past about sweeping mullions across the whole form and it seems like this is probably a whole post for an answer. zachkron@gmail.com

7. Zach,could you please send to my e-mail elena-marhi@yandex.ru the file "Limiting panel size". I started learning Revit forms a short time ago and can't understand exactly your method.
Lots of thanks for really interesting examples!

8. We have an irregular shaped curatin wall, I modeled a project specific panel family and loaded it into our project to replace system panel. When comes to the regular shaped panel(rectangular shape), the coustermerized family replaced the system panel easily, but when comes to the irregular shaped panel(mainly exist at the edges of the curtainwall, where the panel is no longer a rectangular), Revit refused to replace the system panel with the panel I modeled. Is there any way to solve this?