Hi everyone, I'm new to MOI 3D and I really really really love it!
Maybe because I'm in my 3 object, MAYBE I want to do more advanced things... but:

I'd like to accomplish something similar to a mill profile, something really small, like 1/3mm wide and 1mm deep...
...on a curved surface!

I continue to fail.... here are my attempts:



WORKED, BUT ON A BOX - make 2 profiles, project on box, make planar, extrude (1st doubt: wasn't MOI supposed to boolean subtract while extruding the face going inwards?) make boolean difference - Very long process

DIDNT WORK - the same attempt on a curved surface fails (make planar doesn't work)

WORKS, tedious - the 2 projected profiles cannot become a surface using any tool so I tried creating a VERY small rectangle, scale it 1 dimension (depth) and using LOFT. Again, very long and difficult, given the size of the profile


I really tried every combination of actions, almost all actions in the "Construct" menu, with no luck!

What is so easy in my mind (1mm depth profile on the surface) seems so difficult to achieve... why? What am I missing? I'm sure more experienced designers can figure it out right away, please help!!!

Another issue: often, I seem to create cured surfaced, but for my needs, I'd prefer having a depth, like 1mm. Easy way to add depth to a curved surface (let's consider the one I created as prototype).

THANKS -- THANKS -- THANKS -- THANKS -- THANKS -- THANKS -- THANKS -- THANKS -- THANKS --

Hi ioVideoMaker.

Please provide .3dm file of the "remote controller" object.

I think that your attempt with Project and Extrude was close to succeeding, but rather than Planar, try cutting out a piece of the curved surface, to be joined to the extrusion.
Move this curved bottom extrusion 1 mm, and trim it with the edge of the object.
Join and fillet.

- Brian
(This is a mental usage of MoI.)

The last few steps, Trim, Join, Fillet, may instead be Boolean difference of intact solid controller, with the curved bottom extrusion.

ps I missed the part about the groove being 1/3 mm wide, so the extrusion should be two extrusions, one nested inside the other, and only a narrow rounded rectangle strip be cut from the controller...

Hi ioVideoMaker, yes like Brian writes above it would help a lot if you could post .3dm model files for the objects you are describing rather than only screenshots.

re:
> DIDNT WORK - the same attempt on a curved surface fails (make planar doesn't work)

I don't know for sure since I'm not able to examine the object you are talking about but usually to make an indentation on a curved surface you'll need to cut up a portion of the surface and then you can extrude that surface fragment.

Some examples here:
http://moi3d.com/forum/index.php?webtag=MOI&msg=3024.4
http://moi3d.com/forum/index.php?webtag=MOI&msg=4010.4
http://moi3d.com/forum/index.php?webtag=MOI&msg=3318.1
http://moi3d.com/forum/index.php?webtag=MOI&msg=4791.13

- Michael

For learning and practice, I did a "mill-ed" groove on a half cylinder.
There may be better or more simple ways?

Making a rectangular "milled" groove on or into the surface of a solid. The surface can be curved.

This is just an off the cuff summary of (all or most of) the steps that I used.

Object to be milled is half of a cylinder.
"Milled" region is based upon an initial planar rectangle profile curve, but could be a circle, or other closed curve. The milled region is a narrow-ish groove, with shallow-ish depth.
(Or the whole rectangular area could be milled out)

Place the rectangle profile curve in front of the rounded surface of the cylinder.
Duplicate the rectangle with an offset rectangle.
(I used FatLines script by Max, to make two new nested rectangles, and discarded initial profile, but other techniques will work.)

Project the two nested rectangles onto the rounded surface of the cylinder. This produces two new curved "rectangles" curves. Use these to trim the surface of the cylinder into a "picture frame" surface. As Michael mentions, extrude the curved rectangles into the half cylinder.
Move the "picture frame" to the bottom of the extruded depth of the extrusions. Join up the relevant parts, to yield a half cylinder with a "milled" groove.
I avoided the seam of cylinder. Have not investigated Seam effect of cylinder.

(Edit: trim can be used instead of projection, as per Michael's links. The picture frame can be extruded, with set dir, instead...Then boolean(?))

- Brian
After viewing Michael's links, there seem to be various ways to extrude various objects, for a variety of different results. Set dir helped for some ways...
So folks may have different solutions to the problem of milling?
Some kind of Macro script might be nice?

I'll delete the attachment in a few days.

The Offset>Shell command using the picture frame, can be used, instead of extrude...(As far as I can tell...I am getting a joined surface instead of a solid.
But I am quitting now :-)
After a while, I think it is good to start fresh...

- Brian

Hi thank you all for your precious support! I'm really glad I'm in this community!

I'm gonna study all the suggestions in detail, please find here attached my part.
I'm also attaching* a screen recording (hope it's more suitable to understand what I mean) for 2 weird things (IMHO)
*uploading on youtube: https://youtu.be/zDpo6_-guAg

- sweep with one rail creates a hashtag like surface? why??
- sweep with 2 rails creates what I'd like to have, BUT, as you can see there isn't ONE object, but TWO? I don't get why... and I don't get how to get those two as one single object... I tried the two first ideas I went up to, with no luck...

I'm sure I'm missing some philosophical view of MOI that would help me immediately grasp what I should expect from every action...
I'd like to immediately, intuitively grasp WHEN sweeping a closed curve won't create a solid, but a joined surface...
Any good online course for that? Maybe a deep dive into understanding nurbs and topology problems?

 

THANKS AND LOVE -- THANKS AND LOVE -- THANKS AND LOVE -- THANKS AND LOVE -- THANKS AND LOVE --

Hi ioVideoMaker,

re:
> - sweep with one rail creates a hashtag like surface? why??

Can you please post the .3dm file that you are showing in the video?

But my guess without being able to examine the actual geometry is that it's because you have a non-planar path.

A one rail sweep on a path with sharp corners will attempt to produce mitered corners by extending each section and intersecting them with each other but that can be problematic if you have a path that is not either all planar or made up of lines only.

If you can please post the model file that goes along with your question it can help a lot to better understand what you are running into and give better suggestions.

Probably what you want to do there is trim the surface with your curves, then extrude the middle surface piece.

Thanks,
- Michael

re:
> I'd like to immediately, intuitively grasp WHEN sweeping a closed curve won't create a solid, but a joined surface...

It can easily happen if your path curve has sharp corners in it and is also not planar.

When the path curve has sharp corners in it then the sweep basically happens on each section separately and for a one rail sweep it will extend the ends of each section and try to intersect them with each other.

If the path is also not planar then it's easy for those extended pieces to not necessarily make a simple clean intersection with each other as it will with a planar path.

- Michael

re:
> Maybe a deep dive into understanding nurbs and topology problems?

Check out these posts for some tips for people coming from a poly modeling background:
http://moi3d.com/forum/index.php?webtag=MOI&msg=4865.2

But basically for maximum efficiency you want to be working with 2D planar profile as much as possible.

So for something like in your video you could start with these profile curves, a rectangle in the top view
and a wavy curve in the front or side view:



Extrude the rectangle to make a box:



Select the box and run boolean difference and use the curve as the cutting object:



Discard top piece of box:



Repeat the same process with other profile curves, 2 smaller rectangles in the top view and a side view profile that was copied a little bit above:









Now there are 2 pieces:



Select them both and run boolean union to combine them together:




Note, all planar curves were used.

There were non-planar 3D wavy curves that were __!!generated from intersections in booleans!!__ but no non planar curves used directly for constructing.

There are some kinds of cases where you do need to construct things using non planar 3D curves but NURBS modeling really shines the brightest when you are able to get your model formed just from drawing 2D profile curves only. Some 2D profiles generate the extended base forms by extrude, revolve, etc.. and others are used as cutting objects for booleans.

A key concept is that often you want to make your starting shape to be an extended form like in this case you build a box and then cut it with a boolean and discard some pieces.

- Michael

Hi, all there! I've been quiet, but constantly trying to get the most out of my MOI3D practice!
So I tried to follow all the suggestions I got, and practiced a lot... but I went trough some very nasty times!

Here's my best (failed) attempt: what is wrong?




1. I have these profile lines



2. I can loft them (loose, auto, cap ends) and I get and "HANDLE big"



3. Now I move left my 100% sized handle and I scale down my lines (b box, 0,99)



4. Loft again, I should get a 1% smaller handle (let's call it HANDLE 99pc)



5. Now if I create a bounding box point and I align the smaller handle...



6. ...I should be able to boolean subtract them... so this handle should be empty inside...



7. ...but if I create a line to cut it in 2 parts... ...I cannot boolean merge them to get my handle split in 2 parts... but something even more strange happens...



8. the handle has somehow doubled



9. I move on of the handles left... ...and now the same line, boolean merge will split the handle in 2 parts... but should it be empty?



10. MY GOAL was to create a shell of the original handle and then to cut profiles over it using lines and boolean merge like here (final goal cutting away that profiles as Michael told me to)

MY PROBLEMS (excluding private life ones) doing the same exact procedure and got nothing here, but got a shell and was able to cut it through via boolean merge when I saved my parts, opened them, tried the same way. I've been particularly struggling with the boolean merge: once I wasn't able to cut trough it, I added a simple cube behind my handle, cut through it, THEN the boolean merge worked with my handle... like it understood what I meant and finally did it???

I'm sure I'm missing something here, but I really need to have a quick workaround for milling a profile in curved shapes... so long, no luck... (even projecting the profile line on the handle didn't work).

PLEASE HELP: what is the correct solution? I mean a solution that always works with these kind of models... maybe someone has a smarter way? Me, I'm struggling...

MAC VS WINDOWS??? These seems like bugs on my version... (using beta 5 on a Mac)... maybe I should use MOI3D on Windows? Would that be more reliable?

-- THANKS -- -- THANKS -- -- THANKS --

Hi ioVideoMaker, I'd say that the root of your problem is trying to do too much all in one single loft.

Loft is primarily a surfacing tool. You basically want to use it to generate one sheet that has a single shape to it.

In your model you've got a lot of tight bends in your profile curves - those are places where there should be a transition in between different surfaces, usually that is done by having pieces meet at a sharp edge initially and then apply a fillet for the transition piece.

It's difficult to get a good quality surface when you're incorporating a whole bunch of these transition areas right in a single go of Loft.

So a kind of better direction would be to have fewer profiles and generate an initial shape that has sharp edges maybe ignore the very top part to start with and get the main body part set up with a cleaner simpler structure.

Your current one has so many profiles with so many different shapes trying to connect together into a single surface that it becomes stressed and has bunching and buckling in it rather than relaxed and simpler surfaces.

- Michael

So something more like this, here fewer sections and using "Straight sections" loft mode to make the base form:



Then the transitions come from doing a Fillet:



- Michael

And for the top probably extend up the main blocky body and then have a separate dome surface that intersects it with a boolean, something like:







- Michael

Hey io,
If you do the surface grooving first, before all the detailing will help. MoI has an "Inset" Command which has groove options.

THANKS for taking the time to try it!
I'll surely consider your suggestion for next model, 'cause right now I'm in the rigging/animation phase, and (as usual) every problem I just had 5 days ago seems to magically disappear... (everything works, as soon as you don't need it...)

I know I should invest some time in uderstanding good topology, but I just need the quickest way to visualize various options for a prototype and "loft" or "sweep" are just my actual way to go... ..but sometimes I get stuck with these weird (for me) problems...

thanks again, and I'll come back with some useful insight (if I find any)

best regards and happy new year! (to everybody, in the MOI3D community)

:-)