Hello guys,
Please forgive me if I am asking my question in the wrong place. Let me know where is a better place for that.
Normally I do poly modeling in Blender from time to time, but I am totally in love in moi3D and Nurbs since 2 weeks.
I am trying to make my first Nurbs model in my life but I have an issue.
I dont know how to make properly connection I marked as a red color.
It is a rubber strap for apple watch.

Best
Maciek

Hi Maciek, that's a pretty difficult type of model to use for your first NURBS experience. Usually the strongest area of NURBS modeling as compared to polygon modeling is when you are able to form your model primarily using 2D profile curves, some to build solids and others to cut solids using boolean operations.

When you get more into the area of surfaces swooping around in 3D rather than coming from 2D profiles, it's a much more difficult area and it doesn't become as clear cut that NURBS modeling would be better for that type of model than sub-d modeling.

But I would probably try putting a blend surface (Construct > Blend) in as the first thing to try in your particular case though. But also another thing that might be good would be to build the band as a larger object that collided with the body and then boolean those with each other rather than having the band stop some distance away from the body. Making objects punch through each other and then booleaning them together and using fillets to round off sharp corners often tends to be the best workflow for NURBS modeling - building things in a sort of "patch by patch" manner tends to be more difficult with NURBS modeling.

I've noticed that people coming from a poly modeling background often times try to approach things in that "patch by patch" manner and shy away from booleans because they're so used to avoiding booleans in their sub-d modeling. But with NURBS modeling booleans between extended pieces are usually the main way to do things.

There are some tips here for people coming from a poly modeling background, they may be useful:
http://moi3d.com/forum/index.php?webtag=MOI&msg=4865.2

Also if you can please post your 3DM model file as an attachment here that would really help to give you more specific advice.

- Michael

Thank you Michael for very, very quick response.
I will try to do your method tomorrow morning.
And yes, you are right :) boolean was my enemy and now it seems to be the best friend :)


Best
Maciek Ptaszynski

Hello,

You could try thinking how the watch band would look on a flat plane and constructing it using Blend and Booleans. Then flow that straight solid on an arc. This is a quick example, although not at all exactly like your drawing, in fact it is quite rough but may give you some idea about modeling direction.

Hi
You could try this:




















Fileted as Michael suggested.
Keith

Maciek -

I tried the approach of sweeping profile curves around a closed wristband curve.

The orange watch is a rectangular box with fillets.

The orange watch can be boolean diff with the watch band to cut away the unwanted portion of the band.

Ed Ferguson

Hello Guys,

Thank you so much for showing me different directions.
Anyhow it is not exactly what I need.
The part of the strap needs to be exactly shaped like apple watch side. Its like cutout from alu part of the body with the same curve (ORANGE).
I know I am quite close but still I am not able to smooth the edge I marked as (RED), so probably my approach is still wrong.



I tried also with boolens (first I projected curve so its a propare base for loft) but It gave me also something weird artifacts.Cut was not completly smooth.
ANd this is manual adjustemnt work with points so probably no go for proper Nurbs modeling.








I don't give up but I am sure there is 100% accurate and better way to do it :)



BEst
Maciek

Hi Maciek -

Using your 3DM file, I trimmed the wrist band rail further back from the ring, and used just two profile curves to sweep the band.

I selected the edges that make up the opening in the watch and converted into a closed curve, and left in place.

I made of copy of this curve and moved it away from the watch. I then flattened this curve and resized it slightly smaller in width.

I made a copy of the profile curve at the end of the sweep and positioned it away from the end of the sweep.

I mirrored the four curves to the opposite side.

I selected these four curves and made a Loft. The two curves between the sweep and the watch are "helpers" to guide the shape of the loft as needed.

Looks like I'm all out of forum free space to upload the 3DM file :( That's what happens when you upload monster sized tutorials :)

Regards -
Ed Ferguson

Hello Ed,
Thank you for the small tutorial :)
I know I am too picky but this is the reason why I would like to switch from poly to nurbs.
I would like to have perfect shape there.
I tried your method and I had same issue like you.
The weird dent (marked as BLUE) and the curve is not going as precise at it should - more curved and the end of strap is exactly same shape as watch part (marked as RED).



Please check the reference picture. It is really pain in the ass for me :) I am trying it for 15-20 h.

Best
Maciek
:)

Maciek -

I see that the strap flattens and adapts to the shape of the watch at the ends.

I would add more "helper" profiles that mimic the watch profile (top view) to try to force the loft to conform as needed.

Because "History" is enabled for Loft, you can move and resize your profile curves while watching the Loft automatically update.

This is a tedious method to be sure, but as Michael stated, it's more of an organic shape not easily made in NURBs.

Ed Ferguson

Yes you right,
with precise profiles it doesnt fit 100% and with manual adjustments its not 100% precise ;)
Anyway I dont give up yet ;) its a good nurbs lesson for me :)
btw what do you think about the watch itself? Did I make some huge mistakes there?

Best
Maciek

Hi Maicek
It might be worth looking at this video on variable filet. https://www.youtube.com/watch?v=CemIL-wleOw

I have been playing with your file and have come close and I think I could succeed but other things in life need doing.

Having said that Ed is a better modeller than I so it might be best to follow his advice:)
Regards
Keith

Maciek -

This is the best result I can get. It uses 5 profile curves to build the Loft.

I emailed the 3DM file to you as I'm out of allocated space for posting attachments to the forum.

Also, to best evaluate your model, make a render. Sometimes in the MoI display things may not look perfectly smooth, but when you render all is good.

Regards,
Ed Ferguson

Hello Ed,
thank you for your email and help :)

I did it in similar way (pls check the email)
Last questio nis if its possible to close the strap inside the watch (marked as GREEN)





I place it also here cos maybe someone wants to see it :)

Best
Maciek

Maciek -

Filling the gap in the band -

Making extensions and capping off after the fact can be difficult, if not impossible, on complex objects. It's best to avoid making patch work by making the object larger than needed, then cutting away what is not needed.

I would delete the Loft and add one more profile curve (planar) inside the watch. That way you are making the band longer than needed. Try making this new profile curve a copy of the curve that conforms to the watch opening, flatten it using the selection handles (to make it planar), and stretch it a little taller, and wider than the watch. Adjust this curve so the areas that intersect the watch conform to the watch opening.

The resulting Loft should be be a solid because each end is planar.

Now you can create a cutting curve in whatever shape is needed to Boolean away the unwanted band section just inside the watch. The result after the Boolean should remain a solid.

It may be that the band does not conform exactly to the watch opening. If so, you could take a version of the watch that has no opening, and use the watch band to create the opening via Boolean Diff.

How accurate you need to be depends on your application. It's really difficult to try to replicate complex semi-organic objects to exactly match a blueprint.

Ed Ferguson

Maciek -

Here is an idea if you want to fill in the band (But better to make it all from the beginning rather than fill in)

Ed Ferguson

Hi Maciek - yes like Ed writes above usually you don't want to be trying to fill in an empty surface to cap something like that - if you're doing that again it usually means you're trying to build things in a "patch by patch" manner rather than using solids and booleans. With NURBS modeling you would usually get that type of cap by slicing the end of a solid off with a 2D side profile curve, that will leave the imprint of the extruded side profile as the cap.

re:
> I know I am too picky but this is the reason why I would like to switch from poly to nurbs.
> I would like to have perfect shape there.

NURBS modeling may not be the right tool for this purpose though - again as I wrote above NURBS modeling works best when you are able to describe the shape using 2D profile curves.

If the shape needs to be adjusted by a kind of sculpting approach with adjusting the shaping in some very local area, then that usually becomes more related to organic modeling where polygon modeling can work better since polygon modeling can get you that type of fine tuned local sculptural control.

So anyway since you're not working with 2D profile curves or solids very much and since you're also concerned very much with subtle shaping characteristics in a localized area of a surface, it's entirely possible that NURBS won't be the best fit for your needs, or it also may be possible that you'll need to work with the more finicky and advanced type of NURBS surface shaping which MoI is not focused on itself. You may need to take a couple of years of study with Rhino or Alias for example to do that type of thing.

- Michael

Here's how the connection would be made (no focus on the shape of the watch)......



What you want to do is model the watch body and band as a solid in a flat plane. then flow that to a band curve, then cut the connection of the band and body with a single curve from a side view....

Here's another one where I used the "side cut" but then used a sweep to create the band (Sweeping a regular band shape along a curve to meet the face of the side profile cut)... Looking at the underside of the band, I didn't control that well through the sweep, so it messes with the aesthetics of the side profile view. I was going to look at a scaling rail to control this part, but kindof had enough already. Also, someone else showed how to just create multiple profiles along the path using loft, which would do the same to fix the sweep also...

Also, the original side cut is where you get the shape of the end of the wrist band. After I created that and used it to create the band fitted to the body, I deleted the original side cut out of the body, then did a funky blend cap on the end of the band and re-cut that out of the body. It maintained the original profile intent but created a cool organic cavity on the body... I guess it depends on how you want the guts of the body and the band to be connected. I don't have an apple watch.

Anyway,