joint double curvature jumbo

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 From:  Morten (RUMLAB)
4948.1 
Hey.
A friend asked me to give this joint a go, but I am having trouble getting
a smooth, precise surface. The attached picture is done with the Patch tool
in Rhino. Not completely precise. Tried all kinds of curve networks in Moi,
but i always get a visible seem/break (like in the dark area of picture).

Any ideas?

Thanks!
M
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 From:  Michael Gibson
4948.2 In reply to 4948.1 
Hi Morten - usually for something like that you will need to leave a little bit of empty space between the pieces and then put in a Blend surface (Construct > Blend) to make a smooth connection part.

See Mike's mini tutorial here for an example:
http://moi3d.com/forum/index.php?webtag=MOI&msg=4388.55

- Michael
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 From:  BurrMan
4948.3 In reply to 4948.1 
Hey Morten,
It looks like you are trying to mirror the surface result and look for smoothness between the 2? These ends are not planar here, which will create 2 surfaces that deviate from tangent. If you look in the top view, fix these to be planar also and the result surfaces should be smooth.


EDITED: 19 Jun 2012 by BURRMAN

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 From:  Michael Gibson
4948.4 In reply to 4948.1 
Hi Morten, and also if Rhino's Patch is already doing something close to what you want, then just using Rhino to do that part is probably the easiest.

Just slice off some of the inside area where your 2 patches are touching each other so there is a little bit of space in between them and put in Blend surfaces to fill in smooth surfaces into the empty space.

- Michael
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 From:  Michael Gibson
4948.5 In reply to 4948.1 
Hi Morten, the other way you can try to surface something that has an irregular boundary like that is to extend some pieces of the boundary so that they make one longer curved side and then surface that and then cut off some of that surface to make the final end shape, rather than trying to directly construct a surface along all those curves.

So in your case here that could mean something like put in a blend curve between these 2 curves here:



That then basically continues a smooth curve for those top pieces like this:



Repeat that on the other side, join those pieces together and do a Rebuild on them, and then you have a 4 sided boundary like this which can then be surfaced with Sweep or Network:



Then you slice off the ends with a line to get your final shape:






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 From:  Michael Gibson
4948.6 In reply to 4948.5 
3DM file that goes with that previous method attached here.
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 From:  Morten (RUMLAB)
4948.7 In reply to 4948.6 
Ahh. Brilliant! The Rhino Patch tool gives some pretty irregular results,
but it does extend the surfaces and trim them, as your principle,
which could have been a hint.

The mirrored matching was only in desperation, but I didn't see any non-planer curves?

Thank you again.

M
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 From:  Michael Gibson
4948.8 In reply to 4948.7 
Hi Morten - yeah the Rhino patch tool works by initially fitting a totally flat plane through the curves, and then sort of stretches points along the plane normal. It works great for filling in irregular holes where things are not bending around all too much but if you've got areas that curve like 90 degrees away from the plane that will cause problems in those areas.

- Michael
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 From:  Morten (RUMLAB)
4948.9 In reply to 4948.8 
Ok. I also encountered some strangeness with different curves. The patch working as expected on some curves,
and totally unexpected on others. But my biggest issue was the fact that the original flat surface just couldn't
be stretched in a precise way, around the tight bends. And the moi Network function works so well with few curve inputs.

The main thing I sometimes miss from Rhino, is the command window ;)
But maybe I should just get a wacom.
(and maybe the faster trims, although I also dig the visual selection feedback in moi)

Whenever people are complaining about their existing modeler, I always just answer "moi".
But these office people are strangely reluctant to buying additional tools, even as cheap as yours.
"Well we already bought Rhino, now this is not enough?"

Thanks!
M
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 From:  Michael Gibson
4948.10 In reply to 4948.9 
Hi Morten,

> The main thing I sometimes miss from Rhino,
> is the command window ;)

That's one of the things that makes Rhino have a kind of archaic 1990's feel to it...

It is possible to type in commands to MoI as well - the xyz point input box works as a kind of mini command line. If you push Tab to put the focus there you can then type in a command name to launch it.


> But maybe I should just get a wacom.

The main reason for getting a wacom is if you are already very familiar with using a pen or pencil to draw stuff with and it just feels more natural for you to manipulate a stylus than using a mouse.

If you have primarily spent a lot of time using a mouse and that's actually what you are more comfortable with, then getting a wacom is not going to increase your productivity.


> (and maybe the faster trims, although I also dig the visual
> selection feedback in moi)

The problem with Rhino's AutoCAD style Trim command is that it's inconsistent with the regular "noun, verb" type selection sequence. Having some commands work in reverse selection order from others is one of the things that tends to make Rhino more difficult for beginners to learn.

In the future though, I would like to add an additional "QuickTrim" tool that would work like that which would be useful to more experienced users, see here for some discussion on that:
http://moi3d.com/forum/index.php?webtag=MOI&msg=4129.3

- Michael
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 From:  Morten (RUMLAB)
4948.11 In reply to 4948.10 
- Definately very archaic. And I never understood why "pl" is not "polyline" and so
on, to make the autocad bridge smooth.
What I do like though, is the ability to keep my eyes on the model, while just tampering away.

- Good to know about the wacom. I very familiar with drawing, but also a looooong time mouser.
Never really been inclined to go wacom.

- "Quicktrim" looks ├╝ber.

M
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 From:  Michael Gibson
4948.12 In reply to 4948.11 
Hi Morten,

> - Definately very archaic. And I never understood why "pl" is
> not "polyline" and so on, to make the autocad bridge smooth.

I think "pline" is the official AutoCAD command name? I think there is a default alias set up for that in Rhino. It was not really a goal to be a 100% identical AutoCAD clone like some programs shoot for (especially for stuff like only 1 global UCS which was really painful in AutoCAD with multi viewport modeling) - it was more to just generally feel friendly and really easy to pick up for AutoCAD users.


> What I do like though, is the ability to keep my eyes on the
> model, while just tampering away.

There are other things that get in the way of that in Rhino though too, especially needing to hold down shift and control a lot. A lot of the time people will have to glance down at the keyboard when using those modifier keys along with the mouse.

- Michael
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 From:  Morten (RUMLAB)
4948.13 In reply to 4948.12 
yeah, but If you switch between programs during the day, and in one program a polyline is "pl" and in the other it's "pol.
One is "o" for offset, the other is "of" and so on, you just see yourself making at lot of errors.

The problem for me with the shift/ctrl/alt navigation style is the same. I think its very quick
getting used to "blindly" using the buttons, the problem is more, if you have two pieces of software,
with slightly different conventions. Ie. ALT is the orbit for many softwares, while Rhino is SHIFT and so on.

I havn't used moi that much yet, and should probably setup more of my own short cuts. I very much a fan
of shortcuts, and in a way, it's a good thing, that you have to set them up yourself, instead of getting
into the affore mentioned confusions.

M
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 From:  Michael Gibson
4948.14 In reply to 4948.13 
Hi Morten,

> I think its very quick getting used to "blindly" using the buttons, <...>

If you watch people closely while they're using them, you can often see them using their index finger to push shift or control when they're using it as a mouse modifier, instead of the fingers they would use for more regular text typing.

A lot of times that makes for a glance down at the keyboard and then back up to the monitor again, and that's a much larger shift than going to a toolbar button that's at least on the same screen and not at some really different angle.

So really a lot of times things that are heavily keyboard oriented with modifier keys often tend to make people look away from the model, not so much for typing in command names though since that happens with your fingers in regular typing position.

That's one of the factors that helps keep MoI able to work with a more "heads up" type workflow, since you don't have to hold down shift a million times in a modeling session for every time you want to select more than one object.

- Michael
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 From:  Frenchy Pilou (PILOU)
4948.15 
Use of the Wacom pen is very cool for artist who want to make some voluptuous curves by hand inside Moi! ;)
---
Pilou
Is beautiful that please without concept!
My Gallery
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 From:  Ambimind
4948.16 In reply to 4948.10 
"The problem with Rhino's AutoCAD style Trim command is that it's inconsistent with the regular "noun, verb" type selection sequence. Having some commands work in reverse selection order from others is one of the things that tends to make Rhino more difficult for beginners to learn."

I don't know about anyone else, but this statement makes me excited. When you write "[...]"noun,verb" type selection. Having some commands work in reverse[...]" - I wonder if there is an explicit theory somewhere there? - one that links language(and the reasoning it enables), the objective basis of its concepts in reality, and the need to carry that into virtual environments?

Ambimind
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