|
active
Joined: Fri, Jul 17, 2015
0 Posts
No Rating |
Sometimes we start SD in Revit (LT 2014) before we get survey information, so we start modeling the building before we have topo modeled. When this happens, we usually have views set up on sheets and annotations that we want to keep.
We run into problems when we get the survey, model the topo accordingly, and need to adjust the vertical relationship between the topo and modeled geometry (and all associated annotations/sheet setup).
The challenge is that topo is created relative to an origin that is difficult/impossible to control. Here I am talking about the values that are displayed in the topo edit mode; the values in a spot elevation annotation are easy to control and do not necessarily match the values in edit mode. We need the values in editing mode to be accurate so we can easily understand what we're working with while we're editing it.
Behavior of the enigmatic topo origin that I have discovered:
- It is not the project base point nor the survey point.
- It is the location of where the bottom level was when the project was created. If you move that level, though, the topo origin does not move with the level.
- It moves along with everything else when you use "relocate project" or move the project base point when it's clipped.
- It does not move when you move the survey point, clipped or unclipped.
For my sanity, I created a layer called "sea level" that I am making sure stays at the topo origin point. I find it helpful to keep the project base point there, too, but I could move it away if it solved the problem (it doesn't seem to).
So far, I have identified two ways of dealing with this problem, neither of them ideal.
- Lock levels together and move them to where they should be in relation to the topo origin. For example, if the FFE is 200', I move the levels so that the ground floor level is 200' above the topo origin. This method allows you to correctly align the modeled geometry with the topo, and the topo reads the correct elevations in edit mode. However, this messes up any annotation and sheet layout we've already done.
- After creating the topo based on survey values, and seeing that the relationship between the topo and the building needs to change by X feet, select the topo and move it X feet. Make sure spot elevation annotation is linked to the project base point and move the project base point X feet, or however you need to move it so the spot elevations read correctly. With this method, the points are incorrect in edit mode.
Has anyone found a better solution?
|
|
active
Joined: Wed, Aug 19, 2015
0 Posts
 |
Make your site and building as 2 seperate revit models. Specify the coordinates at a particular point in the main building model and then publish those to the site model. Then you can link the site model into the building model and if you insert it using the shared coordinates it will be exactly where you want it.
|
|
active
Joined: Fri, Jul 17, 2015
0 Posts
No Rating |
Thank you for your response, Marmiketin. Modeling the topo in a separate project and linking it in may be the best solution for this particular situation, but it seems like a giant pain in the butt to have what is really one project separated into two.
I know that in order to use building pads, you have to have the topo linked into the building model and the building model linked into the topo model so that you can correctly place the building pad in the topo model.
Are there any other workflow issues I should be aware of when working this way? Will this impact phasing graphics? Cut/fill calculations? Any other best practices you can share about this?
|
Search