topic Deleting small faces/polygons in multipatch datasetts and issues with multipatch footprint in ArcGIS Pro Questions

Deleting small faces/polygons in multipatch datasetts and issues with multipatch footprint

AndreasLorentzen — Thu, 20 Jan 2022 09:03:56 GMT

Hi,

Problem:

I've noticed that several times when i use the CAD to Geodatabase tool and get a multipatch feature it works quite well, utill i use the "Multipatch footprint" tool to create a 2D version of said multipatch feature.

What happens is that the tool sometimes create squares (extent areas?) around certain features, normally when they are really thin (See figure):

in cad file:

Possible Culprit:

It seems like the culprit is small/ vertical (?) poly-faces that bugs up in the tool. I have no other ideas.

Solution:
The best solution would be to remove all multipatch-features or poly-faces smaller or thinner that some critical value. However, i do not know of any tool, method of doing this, does anyone have an idea?

I am also open for arcpy-solutions.

Another solution is of-course to remove all square features later by analyzing either squareness or Areal to border ratio. However, i hope there is a somewhat better method.

Another question:
Is there any word of when we can get the possibility to write and read multipatch-geometry in arcpy? or any help-files on this topic?

Re: Deleting small faces/polygons in multipatch datasetts and issues with multipatch footprint

AndreasLorentzen — Thu, 10 Feb 2022 07:06:42 GMT

As nobody replied, i had to fix it.

What causes the problem?:
thin/vertical elements in the multipatch dateset. When using multipatch footprint, the tool cant create a polygon with vertices on top of each other, and therefore creates a bounding box.

How to implement a fix
So the solution is to remove all squares, taking advantage that bounding-boxes always has the two first vertices share X coordinate and the second and third share Y-coordinate.
Note that you cant use the "group by" option for this to work.

Code

number_of_squares_removed = 0
with arcpy.da.UpdateCursor(in_table=in_features, field_names=["SHAPE@"]) as cur:
    for row in cur:
        try:
            array = row[0].getPart(0)
            if len(array) == 5: # the fifth is the first again...
                #print(str([f"({x.X},{x.Y})" for x in array]))
                if round(array[0].X,1) == round(array[1].X,1) and round(array[1].Y,1) == round(array[2].Y,1):
                    number_of_squares_removed += 1
                    #print("Deleted")
                    cur.deleteRow()
        except:
            print("WARNING: COULD NOT CHECK AND DELETE FROM SQUARE")