Create TopographySurface

[Anonymous]

I want to create TopographySurface that has a shape of concave polygon. With the Method NewTopographySurface i can only create TopographySurface that has a shape of Convex polygon.

[saikat]

The NewTopographySurface() accepts the points using which it would create the polygon. And so if the points of the Polygon were convex, I would expect the topography surface to be convex too. Is it not the case?

Can you provide a minimal VS project with this post using which I can see how having points in Convex Polygon layout still does not help? Please do remember to not send across any confidential information while you send the code/information.

thanks

[Revitalizer]

Hi Habib455,

the TopoSurface constructor always creates a convex hull.

Best regards,

Revitalizer

[Anonymous]

I want to create TopographySurface that has a shape of concave polygon. With the Methode NewTopographySurface() i can't do that. 

[saikat]

Using the Revit product UI itself, I see that every topography surface created turns out to be a convex shaped polygon. And since in most cases API follows the UI functionality/behavior, this probably explains why the NewTopographySurface API only creates the Convex shaped topography surfaces.

Sorry for the bad news.

[Anonymous]

Another way to draw 3D surfaces ? 

[Anonymous]

Hi,

Is this issue resolved?

Im not sure I understand the question.

For example rather than creating a hill do you want to create a valley?

[Revitalizer]

Hi Habib455,

if you don't need to create TopoSurfaces in special but only some sort of faces, you may write DXF files and import them as ImportInstances.

DXF file format is well documented, and it can be written as plain text file.

This may be tedious, but once written, you will have control of each face.

Best regards,

Revitalizer

[Revitalizer · Accepted solution]

Hi Jimi.Clarke.

Yes, the question has been answered.

No, there is no solution to create concave Toposurfaces.

The concave/convex theme has nothing to do with valley and hills but with lateral contractions of the TopoSurface seen from above.

For example, if you have the points for creating a surface formed like an "8", Revit will make a "0" formed boundary for that surface, seen from above. Revit will always create a convex hull from input points, connecting the outermost points to the resulting boundary polygon, thus removing "negative" edges.

Hope that helps.

Cheers,

Revitalizer

P.S. Maybe one of the forum admins may mark the topic as "answered".

[Zsolt.Varga · Accepted solution]

Hi @Revitalizer,

Thank you for the information you provided in your post. 

I went on and marked it as a solution as the current status of the feature in Revit. 

In addition, I went on and generated a wish for a related product enhancement on the Revit Ideas Forum. 

Allow concave geometry for toposurface boundary

I will mark this post as an accepted solution as well in order to encourage users to vote for this improvement wish. 

Thank you all for your participation. 

Best regards,

[Revitalizer]

Hi @Zsolt.Varga,

I've posted a single idea at all, and this is about the TopoSurface topic, too 🙂

https://forums.autodesk.com/t5/revit-ideas/create-nonconvex-topographysurface-revit-api/idi-p/750125...

Edit:

Idea was a result of this discussion:

https://forums.autodesk.com/t5/revit-api-forum/create-split-topography-using-api/m-p/7478163/highlig...

Revitalizer

[Revitalizer]

Hi,

in Revit 2020, there is:

TopographySurface Create( Document document, IList<XYZ> points, IList<PolymeshFacet> facets )

So this issue seems to be solved.

Revitalizer

[Anonymous]

Hallo Rudolf,

could you please help on creating a topo surface from a floor? I get all points from slabshape and Revit creates with non-correct boundary. How can I get those facets?

Thanks a lot!