topic Re: Modeling a complex 3D shape in Fusion Design, Validate & Document Forum

Modeling a complex 3D shape

juliangall — Wed, 16 Dec 2015 16:33:14 GMT

I am new to Fusion 360 but am now familar with most of the things it can do. I wish to produce a model from a moulded plaster dove, which you can see in the attached image. I would like to create a 3D model I can then CNC in wood. I would be grateful for any hints of where to start.

T-splines created in Fusion are great for creating amorphous shapes with smooth changes of surface orientation but not, it seems, the types of shape present in this model. I could just about model the head or body but I don't know how I would then add the texture of the feathers and eyes etc.

I can imagine lofting a shape along a three dimensional curve to create one of the wing feathers or tail feathers but that seems like a very laborious process (20 feathers on one side), and I can't see how I would get a smooth transition of size and shape from one feather to the next. Each feather is curved in all three dimensions.

I've tried to capture the bird using 123D Catch, and this produces a model, but when I import it into Fusion 360 it doesn't have anything like the detail that would be needed to reproduce it using CNC. I tried sticking on the green dots to improve the capture accuracy as the painted surface is rather featureless, but it was still not good enough.

You may say this is not what Fusion 360 is meant for and, if that's the case, any other suggestions (for free products) would be gratefully received.

I'm not asking for detailed instructions here but just a pointer or two for where I should start, what I need to find out more about etc.

Thanks in advance for any help.

Julian

Re: Modeling a complex 3D shape

jeff_strater — Wed, 16 Dec 2015 17:15:27 GMT

Hi @juliangall. Take a look at this thread: how-would-you-model-this-part. @donsmac has a great technique for modeling stuff like this.

Jeff Strater (Fusion development)

Re: Modeling a complex 3D shape

TrippyLighting — Wed, 16 Dec 2015 17:23:38 GMT

I would definitely model the complete dove in the T-Spline environment.

If you are new to modeling with T-Splines or subdivision surface modeling it will likely take you a while to get used to the very differnt way of creating geometry compared to "normal" solid modeling. When I started modeling with subdivision surfaces in Blender, which feels very similar to modeling with T-Splines, it felt all very strange. However, while it is it is laborious in the beginning, I find it to be well worth the effort!

If you also want to create the lattice structure that the dove sits on I would change into theModel environment and use regular solid modeling. Then you can combine the two bodies of the lattice and dove.

As you've already described, scannig is another method of getting the geometry into Fusion 360 but it comes in as a triangulated mesh and you can't really edit it well.

Higher resolution meshes are also a problem as currently there is a limit of about 10,000 ploygons in a single mesh in order to transform it into a brep (solid model) body. there are ways around that but these restriction breaking the mesh into smaller portions using Meshmixer.

However, this model is not so complex that it would be too tredious modeling it in the T-Spline environment and you definitely learn something in the process.