Before I show a way to design a model I’d like to highlight a fundamental concept in Sketchup.
The magic word with SketchUp is
GROUP.
Each group is independent and the drawn objects (lines, circles, rectangles, etc..) remain separated from the surface of the objects in the group.
So we have to organize our project into groups (components), to split the complexity of the project in more simple and manageable subsets (eg, fuselage, tail, gear, wings, etc..). To keep track of the organization of the model is useful to visualize the window of the structure (outliner).
Here we can hide / display, lock / unlock, select / deselect, rename, rearrange the hierarchy and ultimately save the components as separate projects.
The ability to save individual parts as separate projects is extremely useful. When we have designed the model geometry, we could
then work on individual sub-projects to develope their unfold in Pepakura and to apply textures.
When we completed a component (unfold & texture), we can import the new component in the model, substituting the old version.
Below is an example of an organization of the model and an example of the directories where I stored the files of the sub projects.
Further below is an example of a sub-project (the engine) how has been exported from the model on the left and then completed and ready to be imported back into the model on the right.
The Groups and Components are useful also because you can unfold and print the single sub project and test if everything fits good.
Then You can assemble the unfolded parts, any way you want, in the final version of your model.
Finally I imported the last version of the component in the sketchup model.
A hint: It’s a good practice to name in a different manner each version of the component, at less before you import it in the model,
for distinguish it from the original one, but if you want to maintain the same name you have first to purge the unused versions in the
model, selecting in the window menu the model information and then the statistics. Otherwise apparently you cannot import the last
version, because sketchup keeps memory of the previous version deleted.