Saving and reopening projects
The .slp project file keeps a whole working session — inputs, layout, hand edits, diagram and materials list — and refuses to load if it has been altered.
A project file keeps an entire working session, so you can stop mid-design and
come back to it. It uses the extension .slp, for Solar Layout Project, and it
is written and read only by the application itself.
This is separate from exporting. The PDF report, the Google Earth file, the CAD drawing and the Excel materials list are for the people who build the plant. The project file is for you: it is the only thing that lets you resume work rather than repeat it.
What a project file holds
| Kept in the file | Meaning |
|---|---|
| The inputs | Every field in the panel as you left it, including the module, table or tracker, site, structure, topography, inverter and energy settings |
| The layout | The placed tables or tracker units, control rooms, inverters or monitoring boxes, arresters, and the routed cables |
| Your hand edits | Everything done in Sketch Mode — moved and added units, drawn obstructions, hand-drawn and deleted cable trenches, annotations, dimensions and text |
| The single-line diagram | The symbols, wires and text on the drawing sheet |
| The bill of materials | The materials list as it currently stands, including any edits or a loaded template you overlapped into it |
| The terrain data | The elevation model and the ground it excluded |
The File menu
- What it shows
- The File menu open with every item readable.
- How to get there
- Click File in the menu bar.
| Item | What it does |
|---|---|
| New Project | Clears the session and starts from an empty window |
| Move to String / Central Window… | Starts a fresh session in a different design mode |
| Save Project… | Writes the current session to a .slp file |
| Open Project… | Reads a .slp file back |
| Exit | Closes the application |
Saving a project
Use File ▸ Save Project…, or the toolbar's 💾 Save(Project) button, which does the same thing without leaving the plot. Choose a folder and a name; the file type row shows the project extension.
- What it shows
- The save dialog showing the project file extension in the file type row.
- How to get there
- Use File ▸ Save Project… after generating a layout.
- Callouts to add
- Outline the file type row.
Save after anything you would not want to redo — a run whose inputs took a while to settle, a set of hand edits, a diagram you have laid out, or a materials list you have corrected.
Reopening a project
File ▸ Open Project…, then pick the .slp file. The session is restored
from it, and you carry on from where you stopped.
Starting fresh
File ▸ New Project clears the session. Save first if the current one is worth keeping — nothing is written to disk unless you write it.
Moving to a different design mode
The mounting and inverter choices belong to the session and cannot be changed inside it. File ▸ Move to String / Central Window… — also on the toolbar as ⊕ Move to String / Central Window — starts a new session in which the choice is made again. Save the current project before you do, or it goes with the old session. See Choosing a design mode.
The file checks itself when it opens
A project file is a single binary container, not a text file. It carries a checksum computed over its own compressed contents, which is verified before anything is loaded. A file that has been altered, truncated by a failed copy, or is not a project file at all fails that check and is reported as an error instead of opening.
Do not edit a .slp file by hand, and do not try to produce one from another
tool or a script. Any change to its bytes — including a well-intentioned one —
makes the checksum disagree with the contents, and the application refuses the
file rather than loading part of it.
Two practical consequences:
- Copy project files whole. Move them with a normal file copy, and check the copy opens before deleting the original. A transfer that stops partway leaves a file that does not load.
- To get the design out of the application, export it. The exports carry the layout into formats other tools read: a Google Earth file, a layered CAD drawing in UTM metres, an Excel materials list, and the PDF report. See Exports.
Comparing several designs on one site
There is one session at a time, so options are compared as separate project files rather than side by side in one window. A workable habit:
- Load the boundary file, set the inputs your design fixes, generate, and save as one project per option — a portrait table against a landscape one, a derived row pitch against a tighter one you override, arresters on against off.
- Give each file a name that states the variable, not a version number, so the comparison survives being read months later.
- Reopen each in turn and read the same summary columns —
DC(MWp),Full Tbl,ICRand, once energy has been calculated,CUF(%)and the probability columns.
Changing the mounting or the inverter topology is the one comparison that also needs a new session, because those belong to the session rather than the inputs.
Where to go next
CAD drawing export
The layered drawing export — every layer and what it carries, why coordinates are in metres, and which layers are conditional on your settings.
Every parameter and its default
The complete input reference — every field in the input panel, its shipped default, its accepted range, and what it changes.