TL;DR Check the demo video at the end.
We are very excited to introduce a Grouping workflow in 3DTin. It is going to play important role in enabling you to make more complex models with 3DTin.
Last month – out of the blue – I felt like modeling the vertical takeoff chopper from Avatar. The one with two fans on either side that can rotate and point upward or forward depending upon which direction the chopper wants to go. When I started to assemble the fans, I realized how hard it was to do it with 3DTin, even though it should have been very simple. There were two major drawbacks.
1. Placing geometries at exact location w.r.t. other geometries was very difficult.
2. There were so many repetitive parts which should have been copy-pastable, but were not. (All blades of a fan are same. Also the twin fans of the chopper are mirror images of each other. Why draw each one separately)
The reason behind first limitation lies in the history of 3DTin. Since it started as a voxel editor tool, everything is aligned to the boundaries of grid cells. That is why after geometries are rotated they shift a little to align with the invisible grid structure and when geometries are moved they snap to grid lines. The second limitation called for a grouping mechanism that will allow aggregating arbitrary number of geometries together and performing operations on them as single unit, including group cloning.
After nearly a month we are glad that we have solved both of these problems.
To fix the first problem, we had to reorganize some code. It wasn’t that difficult to implement continuous movement, but it took much work to ensure that it won’t break existing sketches. In the new implementation, the rotated geometries won’t snap to nearest boundaries. They will remain exactly where their preview predicts they will be. As for continuous motion of geometries, we have added a “Snap to Grid” toggle button to the bottom left toolbar.
When it’s ON, the geometries will snap to grid-lines as you move them around (just like before). But when you turn it OFF, you will be able to move the geometries in continuous trajectory, without any jumps. To help you judge the exact location of geometry’s edges we have added a position readout panel at the bottom, which continuously displays the location of the geometry.
You will see what I mean in the demo video below.
Let’s talk about grouping before that. You will see a new button added in upper left toolbar – that we call “Select” tool.
You click on the “Select” icon and draw a rectangle over your sketch, trying to capture all the geometries of interest. You will see them getting highlighted as you do this. Once you have selected them, a bar will appear on the top, which will let you perform several operations on this group of geometries. We call this temporary grouping. One of the options in this bar is named “Group”. When you press it, all the selected geometries will become part of a single group geometry, that you can treat as a single unit. You can move it, rotate it, flip it and even clone it to create multiple copies of it. This technique lets you create hierarchy of geometries, which makes big modeling projects very manageable.
To demonstrate what I mean, I created a video as I was creating the Twin fans of the vertical takeoff chopper I mentioned above. Take a look.
If someone wants to complete the entire chopper before me, this is where you go.
Besides these two major improvements, we took the opportunity to fix many other small things too. The Axis dial in bottom right is one example. Also, gone are those wireframe boxes that showed geometry focus, instead we now use geometry outline to do that job elegantly. All the controls are now properly documented with snappy tooltips (thanks to tipsy)
Let me know how do you like it.
3DTin 
the select thing you talked about doesn’t work