If you want to create a landscape base from existing data, your best option is a Toposurface. Revit actually refers to this system family by 2 names: Topography (in Object Styles) and Toposurface (on the Massing/Site Ribbon). But I will simply refer to it as Topo.
When creating Topo, there are 3 options: Place Point, Create from Import Instance, and Create from Points File. But only one of these is really a valid option.
- Place Point. This is fine for modifying existing topo, but not for creating a new one.
- Create from Import – Select Import Instance. This is the most commonly/ easily used process.
- Create from Import – Specify Points File. This will not work for most surveys, resulting in the following error and the points being imported incorrectly.
Before creating the Topo in Revit, there are a few things to check/confirm in your AutoCAD file. Since Revit creates Topo by triangulating/interpolating between points, it is always best to use a TINN as a base. If you do not have Civil 3D and/or were not provided a TINN by your surveyor, you can use contour lines. Just be aware that they do not include all of the point data (unlike a TINN) and thus tend to result in a much more inaccurate surface (once Revit triangulates the points).
In Civil 3D, check your surface style. Make sure triangles are visible and see what layer they’re on.
In Revit, Create from Import and Select Import Instance. Once the survey/import instance is selected a dialogue box will pop up, prompting you to choose the layers that have the correct data. They should match your TINN layers.
And your Topo should have points at all of the triangle intersections, like this:
Because Revit re-triangulates between points, there will be some areas where it won’t match the Civil 3D surface perfectly. Of course, you can go and modify those areas as needed, but it is a pretty good starting point.
In addition, there are several different errors that like to pop up when creating Topo, like the one below. Most of them don’t really mean anything and can be disregarded.