Keeping groups separate

I am new to SU, and trying to follw good practice guidelines by working on Layer 0 initially, and using groups to separate geometry.

I am creating a model of my Georgian cottage for use in restoration and improvment work. I am creating it by tracing over architectural plans, imported into Sketchup and resized to ensure correct scale.

Currently I am tracing the external walls. I have subdivided these into groups as the house has sections built at different times with different heights, foundation depths, materials etc. I intend to allocate these groups to one super group of all external walls.

I created the first group, the main Georgian walls and that went fine. Then I wanted to add a second group, the pre-geogian Farmstead walls, which abut the main Georgian walls. Obviously I want them to be physically linked to the main Geogian walls, but not part of the same sub-group.

My problem is that if I draw the Farmstead walls from the Geogian walls SU appears to add them to the main Georgian walls group. If I start somewhere else, add the resulting edges to the Farmstead walls group, then draw from an edge in the Farmstead walls group to join the Georgian walls group, the resulting edges appear variably assigned to no group, the correct group or one of the other groups, and I am not sure how to reallocate them. There seems to be a create group function but I cannot find an add to group or change group allocation function.

And when I do it this way the faces in the Farmstead group don’t close, I suppose because I am relying on an edge from another group, the Georgian group for the closure. I am not sure how to create a duplicate Farmstead closure edge along a Geogian group edge, and ensure it is part of the Farmstead not the Geogian group.

I eventually found a way to achieve what I wanted, though it is complex and does not lead to a precise junction with the Georgian group. I created the Farmstead walls separately, keeping them separate while I traced them by truncating the walls that were eventually to abut the Georgian group. Face closure was achieved, so I could pull the flat edges up into 3D walls. The separation allowed all the edges in the group to be selected without selecting the Geogian group, so a separate Farmstead group could be made. Then I pulled the relevant farmstead walls so they did abut the Geogian walls. But the abbuttal is not accurate and, as I am tracing from an existing plan I am not sure this technicque will work in all cases.

So my question is whether there is an easier and more natural way to do this. I am sure I am missing sometyhing obvious!

Kind regards


It is easy to forget to open a group for editing then drawing lines in the wrong context, but you can reallocate them to the correct group
Select the edges you want to reallocate, cut them into the clipboard, then find the group you want them to be in and open that group for editing by double-clicking on it, then choose “Paste in Place” in the Edit menu.

If you find yourself getting lost as to which group you’re editing, look in the Outliner window. The appearance of the the icon next to the group being edited changes to a block with a dotted line around it, just like your drawing view. You can also double click on the group in the outliner or right-click and choose “Edit Group” the same as if you were selecting the group in the drawing viewport. Sometimes it is easier to pick them out in the outliner if you have overlapping shapes.

Another thing to consider is that maybe your nested groups are getting too complicated. You could put all the walls on one layer for example rather than a “super group”. This would let you easily hide or show the walls from the layers window. You could do the same to show/hide just the Georgian walls if that’s something you wanted to do.

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Remember, however, to assign a layer ONLY to a group or component, NOT to the geometry (edges, faces) within the group.

And ALWAYS keep Layer0 as the current layer.

I would suggest:
1 Make sure that when you have finished drawing one set of walls in a group, you close that group, so you keep its geometry separate. With the group as a whole selected, give it a name in the Entity Info window.
2 When you start drawing another set of walls, just draw in ‘model space’ - that is, not inside a group.
3 When you finish drawing THAT set of walls, triple click on any part of it to select all the connected faces and edges, then R-click Make Group. Select the group, and give it the appropriate name in Entity Info again.

Or use components instead. Most of the time, they are more useful. But when a set of walls is unique, and you don’t need to duplicate them, a group works well enough.

As @McGordon suggests, you can assign layers to groups - for example, one layer for each period of wall building if you want to be able to turn on or off each individual set of walls. And/or make a ‘supergoupr’ of all walls, assign that to a layer ‘All walls’ to be able to turn off all walls at once, but when ‘All walls’ layer is ‘On’ individual sets of walls can be turned on or off with their own layer.

When you come to windows, doors, and other elements of the building, though, use components.


Thanks very much indeed. Very sorry for the delayed reply I have been away from the forum for a while. I have tried to make up for it by posting something on importing UK LIDAR DTMs as terrains, which I made to work today after much struggling. Probably there is a much simpler way.

I have used the suggestions in both your posts and they work just fine. You should have heard the sign of releif that it is so easy!

I also find that I do need to duplicate edges between component to get faces to close. Makes sense.

Kind regards and many thanks again for your prompt replies.


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