Hi,

I build traditional archery bows by hand and now want to produce them using cnc.

I’m completely new to CNC and have very limited knowledge of CAD. I have been experimenting lately with MoI and Cut3D. I’m placing an order very soon for a cnc router but doubt that I will have the skills necessary to build an accurate model of the item I will be trying to produce.

I’m looking for a person that could model a bow handle using MoI and possibly create a tutorial that I could utilize to better understand how to create more complex shapes. I would ship a bow handle to you to create the model from. If interested please reply and we can discuss the details.

Thanks,
Chris

Hi Chris, do you possibly have any pictures you could post that show the type of shape that you need to build?

For tutorials, I don't think that there is an exact one for that, but there are some other tutorials available on the resources page: http://moi3d.com/resources#Tutorials you could follow along some of those which create some other kinds of models to build up your skill set.

Also a good place to start initially are the introductory tutorials available here:
http://moi3d.com/2.0/docs/tutorials.htm


But yeah a bow handle is actually a pretty complex model since it isn't like most mechanical models where the 2D curves for the model are more obvious. It will probably require a more difficult and more advanced type of approach to build a model like that and you probably will need to work up to it by spending some time building easier models to begin with just to get used to how things work.

- Michael

Hi Michael,

Thanks for your help and information. I have been working with the trial offer of MoI and have gotten a good start there's just more to it than I completely understand at this time. I'll attempt to post a couple of pictures of one of my handles. Keep in mind that the bow limbs bolt on to the handle and are attached in all of the photos.

Thanks,
Chris

Hi Chris, yeah unfortunately a model like that is going to be a pretty advanced and difficult challenge. That's because it's made up of a lot of sculptured surfaces and things blending into one another.

NURBS modeling is best suited for objects where you can create some key curves that define the shape of your object, and then you build surfaces from those curves and can intersect and cut surfaces in some areas to remove material, and then use fillets to round off sharp corners where the surfaces run into one another.

As you get to models where individual surfaces are not so distinct, you basically start to leave this area where NURBS modeling fits in really well and start to get more into the area of organic shape modeling which is usually best done with a sub-division surface polygon modeling program which uses a much different approach than MoI for constructing objects.

Your model here is getting quite a bit towards that area of potentially being a better fit for sub-d modeling instead. But it's in kind of a gray area, it could be possible to do it with NURBS but it will require using a lot more advanced areas of the toolset.

- Michael

Chris, would you post a picture of your 5th photo, only squared up to the camera?
View image may give an assist with "tracing" the photos.

>Your model here is getting quite a bit towards that area of potentially being a better fit for sub-d modeling instead.

Chris,

If you want to try sub-d modelling, then you have a couple of software options among which Hexagon is currently at a 100% discount: http://www.daz3d.com

I don't know Hexagon, I am a die-hard Silo fan, but if Hexagon works as Silo for background images to model after, then look this foreground utility as well: http://www.digitalartistguild.com/mi...tyExplain.html

Here is the beginning of a model, based upon trace.
You can do View Image, and show or hide 3 photos.
Rear photo is not available.
The two "bolts" were used to line up the photo's
Cannot seem to move the photos from the axis planes.

Of course the French crazzy prog Hexagon accept images as background ;)
A very neat interface!
Load it as it's free only during this Februar month!!! (else 149, 95 $) or the trilogy Daz Studio 4 Pro + Bryce Pro + Hexagon 2.5 more 800 $ !!!
http://www.daz3d.com/i/3d/free-3d-software-overview?home_5_btn=start
(Pc, MAC)
By Patrick Tuten

Thanks everyone! I have learned a great deal in just one day. I most definitely will check out daz3d as it looks awesome.

Bemfarmer I will take and post some new photos later tonight when I return home from work. Those photos were taken to display on my website so I see where you would need them squared to the camera.

My biggest obstacle is in rounding things over and making them blend together. Example is in the grip area of the handle. Blocky shapes and sharp edges don’t provide for a pleasing bow. Areas that have compound angles seem difficult for me as well.

One last question that maybe some of you can help me with. When taking a solid drawing from MoI into a program such as Cut3D to set the toll paths do all areas of the model have to be completely closed? What I mean is if I zoom in tight and I can see into the center or hollow of the model will this effect the toll path

Perhaps take a handle out to the bandsaw and slice it into "equal" radial cross sections.
The radial arc at the border between the two wood varieties would help in alignment.
Do a loft. :-))

Just laminating the wood must be a lot of work?

Hi Chris,

> My biggest obstacle is in rounding things over
> and making them blend together.

Yeah this is the particular area where polygon modeling can be easier with, because subdivision surface modeling basically melts down the polygon cage down in all directions to be smooth. But it's a pretty different modeling method than with MoI - in a sub-d modeler you work with a cage of points in 3D and not with drawing curves like in MoI.

But a sort of all melted-together looking blending tends to come more naturally with that sub-d modeling approach.

- Michael

bemfarmer

I think that this is the photo you asked about.

Chris