I'm new to MOI and have a lot to learn. Just wondering how I would model the legs on the stool to match the photo.
The problem is the transition at the bottom of the seat with the legs. The seat has a .5" fillet on the top and bottom. The fillet on the bottom is causing all the issues. Rhino was used to model the stool in the photo. Any suggestions would be appreciated.

Thanks

Hi Bob, is it possible for you to post your 3DM model file with your current progress in it? That usually helps a lot to be able to examine your actual objects when giving some advice.

From your screenshot though, I'd say that one thing that's causing difficulty is these tiny little shelf-like areas in these spots:




Little tiny slivery areas like that tend to cause a lot of problems with filleting because a fillet in MoI will fail if it has to entirely eat away an entire surface.

Is it important for the legs to be totally flat along their sides there, rather than having the same curvature as the table above it? If they were flush with the upper part, that would probably help to start with.

And then you probably don't want to fillet the bottom edge of the table so early, unless that's a significantly larger radius than the other fillets that you also want to do later on. If you want to do several fillets of the same radius, it's better to do those all together so that corner juncture areas can be formed in one single filleting pass rather than doing some fillets earlier on as you've done.

- Michael

Also it looks like you've tried to model the leg as an independent piece from early on - it's probably better for something like this to not do it that way and instead just try and build one top part as just one seamless and more simple structured piece and then once you've got the whole thing built then you can carve that up into separate interlocking parts rather than trying to do things as separate pieces initially. Especially if you are going to have fillets running right through those cut areas, it will make things a lot more difficult for the filleter to try and deal with a lot of separate parts, you'd want to do the fillets on large simple parts and then cut right through the fillets at the end to separate things.

Hope that makes sense...

- Michael

Hi Bob, so something more like this (also see attached 3DM file):




So note there that I've got as few surfaces and edges in the base model as possible, it's not all diced up into little fragmentary parts yet. Then that kind of clean structure can be filleted. Only try to dice things up into further pieces once that filleting has been finished.

It can also help for things like the outer cylinder surface to be just one big surface running all the way down including the outer legs right in that one surface rather than those as separate pieces. What I did in this case was to do them separately with an extruded arc to start with though and then made one big extruded cylinder surface and used Edit > Trim to cut it up and then joined that in place of the 2 separate vertical surface to get a really clean and minimal structured base object. Having clean and nonfragmented structures like this will help avoid a lot of filleting problems.

- Michael

And when I was referring to corner juncture areas, it's these types of spots here:




These types of areas tend to be formed better when you do the filleting more all at the same time rather than sort piecemeal on the surrounding areas.

That doesn't apply quite so much though if the different areas have different sized fillets, if you have some fillets that are larger those can usually be done separately and you want the larger ones done first.

But if you do filleting of pieces with the same fillet radius in separate stages, then try to combine those together, it's pretty easy to end up with lots of little fragmentary sharp spots like you show in your screenshot and which I highlighted in my first reply above.

- Michael

Attached is the File from what I've done so far

Thanks

I want to mention that I'm using the trial version of MOI. Looks like it's version 2 and seems to have several bugs with it. Waiting for version 3 to come out before I purchase MOI.

Michael,

Thanks for the info. I am modeling the leg as a separate item. The leg model will be exported as a STL file into Aspire to generate tool paths for my CNC. The top can be model in Aspire very easily. The issue is making the "Maloof" joints between the top and legs. Those joints need to fit together like a hand in a glove. I have no doubt MOI can do what I need. The issues is my lack of experience with the program. I downloaded the 90 day trial of Rhino and found that program is simply way to complex to learn in a reasonable amount of time.

Hi Bob, do any of the above comments and examples help get you pointed in the right direction?

> I am modeling the leg as a separate item.

As I described above, I would not recommend doing it that particular way if you want to have the leg blended to the table body by using filleting. It would probably be better to model it as a larger all connected object initially (see my example 3DM file above), fillet that, and then once you have the filleting done how you want it, cut the leg off from the main object using a boolean operation as a last step.

If you try to build the leg as a separate piece right from the beginning it will be difficult for it to get filleted, because you will end up with a lot of little fragmented pieces which are not good for filleting.

- Michael

I'm going to try you suggestions today. I will post the results later on this weekend.
Thanks for your help.