Hey guys

I wanted to test how a third party plugin from Modo would convert a sub-d model to a Nurbs-model.

Some of the edges looks abit wonky to me, but it is a solid at least.
What do you guys think, is it a fullworthy CAD-model and is it gonna be able to do all MoI-operations on it?

(I included the .3dm file below)

Hi blindfoldjump, well it depends on what particular operations you want to do - filleting and shelling will not be very likely, but I would think booleans will work fine, here's a quick test:





- Michael

lol............ :o

Hi Michael! Thanks for taking the time as always.
Hmm well...I was hoping to be able to use it as a base-form for a vehicle - cut up the form in a few pieces and then make some clean chamfers and fillets on the edges. Maybe put some smaller details on top of that.

Nice looking swiss cheese you made there by the way ;)

Hi blindfoldjump,

> cut up the form in a few pieces and then make some clean chamfers and fillets on the edges.

Well, if you cut some pieces and get some crisp simple sharp edges around the cut zone, those particular ones might have a chance to be filletable.

But filleting does not deal very well with surfaces that come close to being smooth to each other but are just slightly creased, so for example near the front bottom of your object here it's not a good situation for filleting:






It's also not great for filleting to have edges that suddenly bend and swoop right before they come to a juncture with other edges and there are many of those in your model as well.

Basically I wouldn't expect for filleting or chamfering to work on anything currently in that model but if you introduce some new simplified edges through some cuts those might have a chance.

- Michael

Thank you for a good explanation Michael

If your plugin allows you to change the edge weighting (some PowerNurbs products do allow this, I suspect that's what you have?) you might change the weighting (if you have not already tried this) to allow a creased/sharp edge on the corners you want to fillet in Moi.

Chris: Interesting proposal. I will try that.
Do you use PowerNurbs as well?
In my (very limited) experience there doesn't seem to be a great poly-to-nurbs-workflow. Might as well start making nur bs right away...
...Or perhaps Im doing it wrong.

I've tried the plugin for SolidWorks. The huge advantage in my opinion is that you don't have to create curves & sections to generate a nurbs surface. You can manipulate points, edges or faces on a surface right from the start to get the shape you want, its much more direct I think, and can save quite a bit of time for more organic stuff.

I never had a chance to play with edge weighting (my demo expired), but it seems like it could be very useful for objects where you want a combination of hard and soft surfaces with smooth transitions (blends) between them.

"The huge advantage in my opinion is that you don't have to create curves & sections to generate a nurbs surface. You can manipulate points, edges or faces on a surface right from the start to get the shape you want, its much more direct I think, and can save quite a bit of time for more organic stuff."

I totally agree with you there. A way to get the best of two worlds (at least in theory). However I don't feel Im getting the results I was hoping for. But Im still fairly new to 3d in general and might need to experiment some more to get it right.
Ive tried to use Fusion 360 for the conversion instead, and that seems to get me slightly better results I think.