Questions regarding the models and 3D printing

I can't offer any advice with regards to the fibreglass casting but with your other questions I can try

If you want to split your 3d models into pieces then yes there are a number of applications you can download to do exactly that. NetFabb Basic is what I've used in the past to do this, which allows you to cut models along whichever plane you like (x, y or z). When you say puzzle it together.. I assume you mean model it in such a way that the pieces interlock with eachother. As far as I'm aware there isnt any software to do this automatically for you, but if you're using sketchup then you could quite easily segment the model in these shapes (if you need any help doing this just ask)

Any CAD software will do to make the designs, I use sketchup myself without any issues. You'll have to go to the extension warehouse within sketchup and install the STL export tool that allows you to export your models in the STL file format which can be interpreted by your slicer (the program that splits the model into layers and makes the code for your printer). The only thing to watch out for in term of model quality when you're designing with sketchup is with your curves, the number of segments that the curve is made up of. For example on a circle, when you select the cicrle tool.. in the bottom right corner you should see this

Which pretty much defines how many straight lines the curve will be made up of. Increase this number to make smoother curves, but dont set it too high because it increases your file size pretty fast and your computer might start to lag while designing it. Don't have it too low because if it's too low it will be noticeable in your prints

Hope I helped

I finally got so frustrated with Sketchup I switched to Autodesk's 123d Design. I find it as easy to use but far superior to Sketchup. The main benefit is that with Sketchup you start with a "wire frame" model and then have to try to convert that to a solid which is where the problems begin.

123D Design begins as a solid, there is no conversion. The Autodesk 123D family includes software to Scan 3D objects, model animated creatures, make printed circuit boards and more. As you might expect, that work together for a more powerful production capability than you get with most CAD packages and it's FREE. If you plan a career in 3D design, CAD, machining, etc. the Autodesk brand is certainly one of the best to hang your hat on. You can migrate up the skills ladder into their high power industrial strength software. You also get good support and a helpful community forum (of course, nothing is better than SoliForum .

So, to me (and Tin Falcon) it makes a lot of sense. There are five YouTubes by a college in Colorado, I forget who, that got me versed and running in 123D Design in a few quick hours. Google it.

Good luck with your project.

http://www.123dapp.com/