sry i have write it fix via handy ^^ so i have forget the englisch part:
he has asked why if the issue is at the wallbuilding of the second floor he gets now everytime he loads his game - he get an engine error.
i have answered that i think the system tries it again everytime he reload his game. and that i cant check the code because im not a member of TR and only make the german localization xD
release-491 (x64)
…nehearth/components/building/building_component.luac:124: attempt to index local ‘entity’ (a nil value)
stack traceback:
radiant/modules/events.luac:84: in function <radiant/modules/events.luac:81>
…nehearth/components/building/building_component.luac:124: in function ‘_trace_entity’
…nehearth/components/building/building_component.luac:37: in function ‘_restore_structure_traces’
…nehearth/components/building/building_component.luac:17: in function 'obj’
radiant/modules/events.luac:44: in function 'instance’
radiant/modules/events.luac:98: in function <radiant/modules/events.luac:96>
[C]: in function 'xpcall’
radiant/modules/events.luac:96: in function <radiant/modules/events.luac:86>
Not sure if this is the same or similar it happened when placing the individual blocks but using them as a second floor.
So after the Alpha 14 patch the error is still present
@Wiese2007 Denkst du der Bug wird noch gelüftet was das verursacht?
alpha 15 will be only for fixing and performing so i think yes 
Hi there!
I have try to make my own wall area and bug appear!
there it is:
release-519 (x64)
stonehearth/lib/build_util.lua:750: assertion failed!
stack traceback:
[C]: ?
[C]: in function 'assert'
stonehearth/lib/build_util.lua:750: in function 'create_edge_loop_for_wall'
stonehearth/lib/build_util.lua:758: in function 'create_edge_loop_for_wall'
stonehearth/lib/build_util.lua:758: in function 'create_edge_loop_for_wall'
stonehearth/lib/build_util.lua:758: in function 'create_edge_loop_for_wall'
stonehearth/lib/build_util.lua:758: in function 'create_edge_loop_for_wall'
stonehearth/lib/build_util.lua:758: in function 'create_edge_loop_for_wall'
stonehearth/lib/build_util.lua:758: in function 'create_edge_loop_for_wall'
stonehearth/lib/build_util.lua:758: in function 'create_edge_loop_for_wall'
stonehearth/lib/build_util.lua:758: in function 'create_edge_loop_for_wall'
stonehearth/lib/build_util.lua:758: in function 'create_edge_loop_for_wall'
stonehearth/lib/build_util.lua:837: in function 'calculate_roof_shape_around_walls'
...th/services/client/build_editor/grow_roof_editor.lua:119: in function '_compute_roof_region'
...th/services/client/build_editor/grow_roof_editor.lua:72: in function 'fn'
...ces/client/selection/entity_or_location_selector.lua:202: in function '_get_selected_entity'
...ces/client/selection/entity_or_location_selector.lua:238: in function '_on_mouse_event'
...nehearth/services/client/selection/selector_base.lua:115: in function '_mouse_cb'
stonehearth/services/client/input/input_capture.lua:49: in function '_dispatch'
stonehearth/services/client/input/input_service.lua:55: in function '_dispatch_input'
stonehearth/services/client/input/input_service.lua:12: in function <stonehearth/services/client/input/input_service.lua:11>
Hey there @chugo, welcome to the Discourse (err, first post, seems you’ve been lurking around for a while 
)!
From the screenshot you provided it looks like you used free standing walls on the second floor. Those walls do not work with the roof system at the moment (as you found out)! I would suggest undoing the free standing walls and using the standard walls tool. That should allow you to build the roof without error.
I know that.
I dont know where post the bug list.
tried placing a roof over manually placed walls with slabs on some part of the building.
release-524 (x64)
stonehearth/lib/build_util.lua:750: assertion failed!
stack traceback:
[C]: ?
[C]: in function 'assert'
stonehearth/lib/build_util.lua:750: in function 'create_edge_loop_for_wall'
stonehearth/lib/build_util.lua:758: in function 'create_edge_loop_for_wall'
stonehearth/lib/build_util.lua:758: in function 'create_edge_loop_for_wall'
stonehearth/lib/build_util.lua:758: in function 'create_edge_loop_for_wall'
stonehearth/lib/build_util.lua:758: in function 'create_edge_loop_for_wall'
stonehearth/lib/build_util.lua:837: in function 'calculate_roof_shape_around_walls'
...th/services/client/build_editor/grow_roof_editor.lua:119: in function '_compute_roof_region'
...th/services/client/build_editor/grow_roof_editor.lua:72: in function 'fn'
...ces/client/selection/entity_or_location_selector.lua:202: in function '_get_selected_entity'
...ces/client/selection/entity_or_location_selector.lua:238: in function '_on_mouse_event'
...nehearth/services/client/selection/selector_base.lua:115: in function '_mouse_cb'
stonehearth/services/client/input/input_capture.lua:49: in function '_dispatch'
stonehearth/services/client/input/input_service.lua:55: in function '_dispatch_input'
stonehearth/services/client/input/input_service.lua:12: in function <stonehearth/services/client/input/input_service.lua:11>
manually created a roof out of slabs. they are building it without problems so far. just one weird thing: they are building scaffolding within scaffolding.
Edit: turned out this a unbuildable one.the idea with making the roof manually out of slabs wasn’t that good. since both roofs (the smaller one could be done with automatic computing) touch each other they are made into one object… so walls for the small storage room in 2nd floor are never built.
also automatic building computing seems to have problem with larger buildings or i just broke it:smiley:
Seems be still alive …
Summary:
release-537 (x64)stonehearth/lib/build_util.lua:748: assertion failed!stack traceback:
[C]: ?
[C]: in function 'assert'
stonehearth/lib/build_util.lua:748: in function 'create_edge_loop_for_wall'
stonehearth/lib/build_util.lua:756: in function 'create_edge_loop_for_wall'
stonehearth/lib/build_util.lua:756: in function 'create_edge_loop_for_wall'
stonehearth/lib/build_util.lua:756: in function 'create_edge_loop_for_wall'
stonehearth/lib/build_util.lua:756: in function 'create_edge_loop_for_wall'
stonehearth/lib/build_util.lua:756: in function 'create_edge_loop_for_wall'
stonehearth/lib/build_util.lua:756: in function 'create_edge_loop_for_wall'
stonehearth/lib/build_util.lua:835: in function 'calculate_roof_shape_around_walls'
...th/services/client/build_editor/grow_roof_editor.lua:116: in function '_compute_roof_region'
...th/services/client/build_editor/grow_roof_editor.lua:78: in function 'fn'
...ces/client/selection/entity_or_location_selector.lua:233: in function '_get_selected_entity'
...ces/client/selection/entity_or_location_selector.lua:269: in function '_on_mouse_event'
...nehearth/services/client/selection/selector_base.lua:115: in function '_mouse_cb'
stonehearth/services/client/input/input_capture.lua:49: in function '_dispatch'
stonehearth/services/client/input/input_service.lua:55: in function '_dispatch_input'
stonehearth/services/client/input/input_service.lua:12: in function <stonehearth/services/client/input/input_service.lua:11>
Steps to reproduce:
1: WNE
2: WNE
3: W
4: ES
5: WES
3rd floor none - more like a tower
Expected Results:
Getting any roof
Actual Results:
Getting LUA exceptions
Notes:
Attachments:
Version Number and Mods in use:
release-537 (x64) no mods
System Information: