I have a lot of buildings at a 45 degree angle in my map. Due to the difficulties involved with it, I chose not to make any buildings at angles other than that (like 30 or 60 degrees).
With a 45 degree angle, your brush outlines will still be straight and smooth in radient, making it easier to see that your angles are accurate.
I had the same problem when using Cntrl G. I originally built my buildings straight on the grid and then rotated them 45 degrees. Using the Arbitrary rotation tool really trashes them because I think it automatically snaps the pieces to the grid. The Free Rotation tool (r key) will keep your pieces together, but since my brushes were not on the grid, I had invisible parts like yours. To fix that, I had to snap the building to the grid 1 piece at a time. Sometimes it was easier to rebuild the part from scratch.
I found it much harder to work with Cntrl G when using a grid size of 1. By doing that, it was much harder for me to determine if my brushes were exactly at 45 degrees. So it made mitering my walls, and alignment much more dfficult because I would sometimes have gaps. Instead, I used a grid size of 16 (The thickness of my walls) or 8 depending on where my brushes needed to fall. This often lead to changes in my original dimensions or brush placement in order to keep to this gridsize. But that was far more preferable and it made the brush placement a lot cleaner in radient.
Most people will tell you that it is easier to just build the building at an angle and not rotate it. I agree with that in theory. But in practice, I found a lot of structural forms are just far easier to create and rotate, than to build at an angle -- particularly if you need to make any 2 point clipping to get the shapes. Other times, I would find that rotation mangled a brush so badly that was far simpler to rebuild at the angle.
Since I was kind of developing my construction techniques on the fly, I took 3 complete revisions of my map for me to get a workflow that made sense and created complex shapes at an angle. So here are some tips I would suggest you try out to see if they work for you:
- For major structures, try to stick with a 45 degree angle. (MJ's latest map is the only one I've seen with oddball angles that work. I wouldn't mind seeing a top down view of his walls in radient)
If the structures are simple, building on the angle to begin with will probably save a lot of time.
If you are rotating a very large complex building, save the file before you rotate, and again before you deselect the brushes. Radient crashed a lot on me after I deselected my building. Save first, then deselect. If radient crashes, your brushes will still be saved in their rotated state.
Build a template map first using large brushes as bounding boxes for each building and to outline their position and rotation. This is a good way to check scale and playabilty of your design before you even begin actual construction.
Since my buildings were so complicated, I created a .map file for each one. Save out each template building, and develope them separately. I made a prefab with a skybox and player start that I could import into each .map file. This compiles so much faster and helps you to focus on any glitches right away.
If you have to build the building straight on the grid, and then rotate it, expect that it will not accurately fit with your original template. But since you will want to snap it to the grid after rotation, you have the opportunity to alter dimensions to get it closer to your original boundaries.
Keep your wall thickness and your gridsize to 16 or 8. Reduce the grid size only when necessary to fit in your details like windows and stairs, who's dimensions might fall at 8 , 4 or 2 on the grid.
Try to place your buildings using the major gridlines that occur every 64 units. If you need to move a building into position, If you Top view is zoomed out really far, you can still see these gridlines in radient.
When you need to snap a large building to the grid, Make the entire building detail. Start with the ground floors. Make them structural, and filter out the details. That way you can focus on snapping a little at a time working your way up to the roof.
If you rotated stairs, chances are that is too much work to resnap everything. So just rebuild 1 stair, and delete the rest. Duplicate the fixed one.
I'm sure you will come across a lot of things that are simply easier to rebuild from scratch at an angle instead of trying to snap the rotated version. I have 6 major buildings in my map and I actually rebuilt each one from scratch after rotating the original. But it was so much easier to do when I had the rotated one as a placement guide.
Anyway, these are just some things that work well for me. You can try what you like, but I strongly recommend you at least stick to 45 degree angles, and a grid of 16 or 8.
!!