Subdivision - duplicates being created

11-28-2014 03:55 AM
Occasional Contributor III

Version = 2014.1

Input  = Shapefiles

My shapefiles represent generalised footprints of groups of buildings so my first step is to Subdivide my shapes into individual footprints using the subdivide tool.

I start with 666 objects in my layer (a small town) but after subdividing I have almost 400 000 - this is ridiculous and not a number my computer can reasonably deal with - from a visual check I estimate that my largest initial object is subdivided into no more than 50 objects (this should mean the absolute maximum number of objects I should end up with is 30 000).

Here's a smaller example to illustrate:

Input = 2 objects

Subdivide settings - see imagesubdiv settings.jpg

Result - 31 objects, however visual count suggests there should only be 20 - see image.footprint count.jpg

It appears that some footprints have been duplicates - see image duplicate.jpg

ETA -- I seem to get the same outcome in v2012.1

ETA_2 -- Attributes get completely screwed up too.  So in my first example (666 initial shapes --> ~400 000 objects), I look at one footprint and I find that there are 127 duplicates - and all of them have different attributes i.e.

Duplicate1:  Category = RES, Area = 3005

Duplicate2:  Category = RES, Area = 2676

Duplicate3:  Category = COM, Area = 17165

Duplicate4:  Category = IND, Area = 22046


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2 Replies
Occasional Contributor III

Hey ..

I'd say send this together with a test dataset to

Ok ?


Matthias Buehler

Head of 3D Technologies

twitter: @MattB3D


Garsdale Design Limited

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Occasional Contributor III

FYI - this has been confirmed as a bug:

BUG-000084296: Skeleton Subdivision operations in CityEngine produce duplicate geometries irrespective of parameter settings.

Because the bug has only just been raised it's not yet known if it will be resolved in the next release of CE.

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