What would be a good 3d modeller for children aged 8-14(approx)? it would need to be free and approachable. a school technology program i am working with wants to integrate 3d printing into their curriculum and i want to present to them the best open-source option available right now. cheers.
@Onyx_Ashanti while not geared towards cad or 3dprinting, one of the open source modelling programs I find the most accessible would be Wings3d : http://www.wings3d.com/ lightweight, very easy to start building shapes with
edit: it can export to a wide array of formats (including stl) as well, so it makes it completely useable for 3d printing of course
The free offerings from Autodesk (123d Make, 123d Catch, etc…) Are very approachable. They are all available as iPad apps and the main modeling program is also an online version as well. My son loves to just play with them.
tinkercad is the simplest
Maybe Sculptris is an option? http://pixologic.com/sculptris/
It’s not open-source. But there are no real open-source solutions for what you want (easy access for kids)
Else, Minecraft is very accessible for kids. It’s not free, and not a real 3D modeling tool. But it is easy and fun. And there are a few options to turn Minecraft creations into 3D printed objects. (Cura offers one)
i was looking at thinkercad as well, but the seem to have a free “trial” type system now and i dont want to suggest something that is going to be a monthly subscription. i will investigate the rest over the next couple of days. thank you! any insight in regards to children, cad and repraps, is greatly appreciated. I think combining building a reprap, as a class of individually, then jumping straight into parametric modelling, is the way to go. my first thought was to suggest freecad then i realized i was out of touch. any ovther approaches or combination of approaches that anyone might suggest?
All modeling programs i used work the same way. Draw shape in 2D, boss extrude and cut extrude. They’re just not simple. Your kids will have to learn how to do that.
That taken in concern, google sketchup may be an option. It’s free, and well supported. (For advanced modeling and error free models , you wnant to use another program.
To correct errors from the models made with sketchup (you can’t directly convert the model to gcode) you need netfabb studio. It is free for download and fixes most problems in your models.
@Onyx_Ashanti
I see nothing in the pricing plan, in the TOS or in my account that says that the free tinkercad account would end or become paid. This is backed up by the fact that it has limited features. At worst new free accounts could stop to be offered.
Blender is free.
The new version includes a 3d printer add-on.
Blender is a lot. But it’s not easy to use.
I would pick Tinkercad for the older kids and 3Dtin for the younger kids. They are both online - allowing kids to do homework and doing the print job (if one is being used) in class. However - it depends on what you are envisioning your models to be. Neither of these are good for organic models. DAZ3D with Hexagon might be of service in that case.
You mentioned hitting parametric models out the gate. OpenSCAD would be a choice, but I know nearly nothing about it.
You want 123d until the 14 year olds. Very few even at 14 will want more, and for them you can prob get free inventor licenses off autodesk. They love hooking kids on their software.
Anyway, I’m teaching 3rd graders 123d design this year because it has rock solid Boolean combine/remove functions. So you can have them build everything out of squashed primitives which is 100x easier for them than learning about meshes or the various functions in even a basic “real” cad program.
I am also going To link to this thread when i send my recommendations. much appreciated!
The suggestions here are good, but Onyx Ashanti did mention “the best open-source option available right now”. 123D and Tinkercad are not open source.
Unfortunately there is nothing open source that rivals with the closed-source options in ease of use right now. Shapesmith.net is interesting but a bit harder to grasp, and not as user-friendly.
A student is working on an interesting program called Kubos intended for kids, he said he would release it under an open source license once he’s done, in July.
I know of it because he asked permission to use FreeCAD’s icons on the FreeCAD forum. 
Sure hope his project pans out!