# Assertation failed: create\_edge\_loop\_for\_wal

**URL:** <https://discourse.stonehearth.net/t/assertation-failed-create-edge-loop-for-wal/15809>\
**Category:** Previous Build Reports\
**Created:** [August 23, 2015, 7:07am UTC](https://discourse.stonehearth.net/t/assertation-failed-create-edge-loop-for-wal/15809 "2015-08-23T07:07:35Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![BennX](https://avatars.discourse-cdn.com/v4/letter/b/5f9b8f/32.png) [@BennX](https://discourse.stonehearth.net/u/BennX)\
**Post date:** [August 23, 2015, 7:07am UTC](https://discourse.stonehearth.net/t/assertation-failed-create-edge-loop-for-wal/15809/1 "2015-08-23T07:07:35Z")

</div>

I tried to build some kind of townhall but if i try to add a roof it fails and crashes

```
release-453 (x64)stonehearth/lib/build_util.luac:277: assertion failed!stack traceback:
[C]: ?
[C]: in function 'assert'
stonehearth/lib/build_util.luac:277: in function 'create_edge_loop_for_wall'
stonehearth/lib/build_util.luac:280: in function 'create_edge_loop_for_wall'
stonehearth/lib/build_util.luac:280: in function 'create_edge_loop_for_wall'
stonehearth/lib/build_util.luac:280: in function 'create_edge_loop_for_wall'
stonehearth/lib/build_util.luac:280: in function 'create_edge_loop_for_wall'
stonehearth/lib/build_util.luac:280: in function 'create_edge_loop_for_wall'
stonehearth/lib/build_util.luac:280: in function 'create_edge_loop_for_wall'
stonehearth/lib/build_util.luac:280: in function 'create_edge_loop_for_wall'
stonehearth/lib/build_util.luac:280: in function 'create_edge_loop_for_wall'
stonehearth/lib/build_util.luac:280: in function 'create_edge_loop_for_wall'
stonehearth/lib/build_util.luac:280: in function 'create_edge_loop_for_wall'
stonehearth/lib/build_util.luac:308: in function 'calculate_roof_shape_around_walls'
...h/services/client/build_editor/grow_roof_editor.luac:48: in function '_compute_roof_region'
...h/services/client/build_editor/grow_roof_editor.luac:31: in function '_filter_fn'
...earth/services/client/selection/entity_selector.luac:52: in function '_get_selected_entity'
...earth/services/client/selection/entity_selector.luac:70: in function '_on_mouse_event'
...earth/services/client/selection/entity_selector.luac:80: in function '_mouse_cb'
stonehearth/services/client/input/input_capture.luac:26: in function '_dispatch'
stonehearth/services/client/input/input_service.luac:14: in function '_dispatch_input'
stonehearth/services/client/input/input_service.luac:1: in function <stonehearth/services/client/input/input_service.luac:1>

```

 ![](https://us1.discourse-cdn.com/flex022/uploads/stonehearth/original/3X/e/6/e6a1f0db99308950f50a0e4607686159acff5f6a.jpg)

 ![](https://us1.discourse-cdn.com/flex022/uploads/stonehearth/original/3X/8/7/870f8442b196d011286c3f211b5f2f0f45e590c8.jpg)

---

<div class="post-metadata">

**Author:** ![Chymor](https://sea2.discourse-cdn.com/flex022/user_avatar/discourse.stonehearth.net/chymor/32/18486_2.png) [@Chymor](https://discourse.stonehearth.net/u/Chymor)\
**Post date:** [September 4, 2015, 5:12pm UTC](https://discourse.stonehearth.net/t/assertation-failed-create-edge-loop-for-wal/15809/2 "2015-09-04T17:12:30Z")

</div>

Hi

I messed around a bit and found a clear way to reproduce this:

1. Build anything which have an “inner” wall. This screenshot is the easiest construction I’ve managed. It’s built by a few lone walls.
2. The key point is that the walls are connect, forming several possible roofs.
3. Select the roof tool and mouse over the walls and this error occurs.

 ![](https://us1.discourse-cdn.com/flex022/uploads/stonehearth/original/3X/8/7/87f8ea8ca86d3ce52cd55b5c60485f859f886e2e.jpg)

This has no other impact than being unable to build a roof on this house, everything else, including remove building works as expected.