<p>I have a 3d city model that is a collada file which consist of many triangles. When I select the model in a 3d software all buildings are selected. But I want every building to be selectable separately, is it possible? Are there any methods or algorithms that define which triangles belong to a building in a 3d model that consist many buildings and triangles?</p>

CC BY-SA 3.0
2016-08-22T15:35:21.550Z
Do the buildings have any properties that would help distinguish them? Are they disconnected items, or is the city a single connected mesh with the buildings rising from a plane?
trichoplax is on Codidact now
CC BY-SA 3.0
2016-08-22T17:21:08.150Z
yes absolutely second one a single connected mesh
Ziya6161
CC BY-SA 3.0
2016-08-22T17:55:02.320Z
It's worth editing to include that in your description.
trichoplax is on Codidact now
CC BY-SA 3.0
2016-08-23T10:32:44.027Z
Then it really depends on the buildings. Are all your buildings just cubes? Or at least convex? And is the ground plane really just a plane or has it terrain?
Dragonseel
<3d><mesh><polygon>
In a polygonal mesh 3d model which consist of triangles is it possible to separate different objects?
Ziya6161
# In a polygonal mesh 3d model which consist of triangles is it possible to separate different objects?

(Asked by: username_0 on 2016-08-22)

I have a 3d city model that is a collada file which consist of many triangles. When I select the model in a 3d software all buildings are selected. But I want every building to be selectable separately, is it possible? Are there any methods or algorithms that define which triangles belong to a building in a 3d model that consist many buildings and triangles?

**Tags:** 3d, mesh, polygon

> **Comments:**
> **username_1**: Do the buildings have any properties that would help distinguish them? Are they disconnected items, or is the city a single connected mesh with the buildings rising from a plane?  
> **username_0**: yes absolutely second one a single connected mesh  
> **username_1**: It's worth editing to include that in your description.  
> **username_2**: Then it really depends on the buildings. Are all your buildings just cubes? Or at least convex? And is the ground plane really just a plane or has it terrain?  

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## 0 answers

