User Manual
The toolbar
Start from the upper-left, each button in the toolbar is explained as follows.
Right click on the tab (or use the dropdown menu for touch devices) will expose actions related to tabs (such as cloning projects and close multiple tabs at once). Drag the tabs to re-order them.
How to use
As you create a new project, you will see a basic tree with two edges (which is the minimal number of edges allowed in the app in order to make structural sense). First, you should decide what the structure of your model should be. In order to edit the tree, click on any node and use commands in the Option panel to modify the tree. You can add nodes, delete leaf nodes, modify the lengths of edges, and perform some advanced operations such as edge splitting and merging end vertices. You can also rearrange the position of the nodes on your sheet by dragging them around. It is also suggested that you name the leaves to help identify them with the flaps.
Since v0.8, you can cut, copy, and paste nodes, which lets you duplicate or move branches of the tree structure elsewhere, or even paste them from one project into another (including projects in other open BP Studio windows or tabs). When you copy a selection of nodes, the selected nodes are divided into branches by connectivity, and each branch is copied together with "the edge that connects it to the rest of the tree"; then select any node and paste, and those branches will be attached under that node. Only branches that connect to the rest of the tree by exactly one edge are copied, and other parts (such as nodes sandwiched in the middle of the tree, or the entire tree) are skipped; after copying, the selection shrinks to the part that was actually copied, so that you know which nodes were copied. Cutting follows the same rules as deleting nodes, and only the branches that actually get deleted are copied. If nothing can be copied, a notification will appear in the upper-right corner of the screen. Pasted nodes are placed in nearby empty spots, and flaps keep their original width and height.
Once you have the desired structure, go to the layout view and start experimenting with different combinations of flap locations. BP Studio will try its best to find stretching patterns for those flaps that has overlapping with their corresponding rectangles (but not with their corresponding circles) and try to determine the shape of all flaps and rivers automatically. For a very brief account of the method of generating stretch patterns used in this app, see [2] and [3].
When you finish your design, you can save your project, save the entire workspace, or export the design to CP/FOLD formats for further editing in other softwares (such as Oriedita). Note that the exported CP is a so-called "generic CP", which, strictly speaking, is not flat-foldable (as it doesn't handle the directions of the hinges, among other things). Such a CP is meant to give you a starting point without having to redraw everything from scratch.
The default colorings of hinges, ridges, and axial-parallel creases follows Lang's convention in his book, but you may also customize them in the preference dialog. For clarity, only the axial-parallel creases of the stretching patterns are shown, but you should have no problem figuring out the rest by looking at the ridge creases.
Layout optimization
Under the tools menu one will find "Optimize layout" introduced in v0.7. This tool uses methods similar to those of TreeMaker to find efficient packing solution for your design. There are two layout methods: either use your current layout as reference (and the optimizer will try to improve it as much as possible), or let the optimizer generate several random layouts and use the most efficient one among them. In the first method, there's also an option "Try variations of the current layouts", which will also try slightly different arrangements of flaps to see if the efficiency can be further improved.
Keep in mind that the optimizer is purely numerical and does not fully take the aesthetics of the packing into account; although this has been greatly improved in v0.8, the resulting layout can still be somewhat messy, and typically you will have to manually rearrange the result to get a cleaner layout.
Tip: Some of the steps in the computation can be skipped. By skipping some of the steps, you can also use this tool to simply spread the flaps apart after you have done constructing the tree. However, doing so could lead to less efficient layouts.
Check layout
Under the tools menu one will find "Check layout" introduced in v0.8. This tool checks for some layout issues common among beginners, and gives suggestions for diagnosis. Currently the following items are checked:
- Invalid overlaps
Such overlaps are shown as red regions on the screen by default, indicating that the flaps are too close to each other, and such a layout cannot possibly be folded. You should spread the flaps apart appropriately so that there are no red regions in the layout. If you still cannot eliminate all the invalid overlaps after spreading them as much as possible, you should enlarge the sheet instead. You can also use the optimization tool to spread the flaps automatically. - Stretch patterns not found
It is not always possible for BP Studio to find working stretch patterns in every valid layout. This doesn't necessarily mean that your design is invalid, but BP Studio is not yet able to construct a valid CP for you at this stage. Such cases are marked with question marks on the flaps involved.
So far the author has implemented enough algorithms for finding patterns for any valid layout with two flaps and for most valid layouts with three flaps, and many stretch patterns involving four flaps are also implemented in v0.8. The author will continue to implement more algorithms for more complicated patterns. Until the implementation covers your needs, you may try layouts with simpler valid overlaps and looser arrangements of the circles, to increase the chance of finding a valid solution. - Uncovered regions
Every region on the sheet should belong to some part of the model, so your design should have the entire sheet covered by flaps or rivers. This check shows the uncovered parts as yellow regions by default. You can fill those regions by increasing the width or height of the nearby flaps, or simply by adding a new flap there (even if you might not need it) to fill the space. - Broken ridges
Inside the sheet, all the ridges (red lines by default) should be connected to each other, and no ridge should terminate abruptly inside the sheet. There are necessarily some broken ridges around the uncovered regions, and this check marks the other broken ridges with red dots on the screen. You can resolve the issue by adjusting the positions of the flaps so that the ridges are connected. - Unnatural rivers
BP Studio infers the courses of the rivers from the arrangement of the flaps automatically, and in some cases the algorithm concludes that "the river covers more regions than necessary", which is shown with blue diagonal stripes by default. This means that the river you arranged implicitly involves meandering, which is not yet supported by BP Studio, so BP Studio cannot turn such a river into a CP. You can resolve this by filling the excess regions covered by the river, in the same way as filling the uncovered regions.
Current limitations
In addition to the limitations mentioned in the previous section, BP Studio hasn't implemented the notion of elevation or half-integral unit structures for the moment. But you can widen or heighten your flaps by setting their width or height, and use them to create elevations in your final model. You can also use integral structures to roughly represent the space occupied by the half-integral structures, and transform them into the latter in your folding process. Meandering rivers might be represented similarly by using stub flaps, or you can just pretend that it's there and fold your thing anyway.
Other features such as tilted grid and optimization conditions are also planned.