split lines in sweep  1-20  21-31

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 From:  rhumba
744.1 
Hi,

I'm really enjoying moi and just have a small query on the whole split/joined lines malarky.
I've got a bit of brain block and can't work out why, for example, if you join two lines (that meet and are tangent at the join) together then use those lines as rails in a sweep, then the resulting surface's lines are split where the original split was before the join (though the surface is one whole one, not split up). That means for some nice blending of these surfaces later on, I find I need to recreate the line for the sweep with one continuous freeform line in order to get clean results, so that surface edges are not split up unexpectedly.

Without taking care of this stuff I find things can get messy quick, where later on these are used in boolean operations etc. For blending you really seem to need unsplit lines, and since you need to select the surface edges in order to perform the blend u cannot use a 'joined' one.

Another case, but slightly different is revolving from a profile made up of joined lines. eg. draw 2 connected freeform lines that are tangent where they meet (or blend two existing lines) and join the lines together, then revolve. The surface is split into several different surfaces even though the original lines were joined beforehand. So this would create unnecessary splits when used later on...

So any light anyone can shed on this stuff would help me a lot!
Thanks
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 From:  Michael Gibson
744.2 In reply to 744.1 
Hi Rhumba, can you please post a .3dm file with some examples of what you're describing? That would help clarify things.

It sounds like the main issue that you're running into is that Blend is kind of bit too "bare bones" right now, it doesn't let you pick a set of edges to blend between, you can only blend between 2. I might be able to tune this up, I'll take a look.

One thing you can do as an alternative right now is to construct things so that they touch along a common edge, then join them together and use Fillet instead of Blend. Inside Fillet there is an option to do a blend style shape as well, that ends up being the same thing as Blend, just with it trimming back from the common edge to make some room whereas Blend doesn't do any trimming and expects there to be a gap between edges.

- Michael
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 From:  WillBellJr
744.3 In reply to 744.2 
My understanding of what he's asking is if you create a line using two individual segments >joined together< and then sweep that, you'll get an object with a break or seam where the two lines were joined. (Technically even though the two individual lines were joined into a single line, there still remains a >point< between the two causing the seam)

If I'm correct, then it's a matter of showing the points on the line and deleting the >center point< of the two joined lines before performing the sweep thereby creating a clean singular surface (I have to test this theory - my dev machine here doesn't have an internet connection...)

I've run across this as well but know how to "avoid" it. But basically when a two objects are joined, they're not made continuous (as in the case with two simples lines joined together for example) so instead of two points after the join, you get three.

I feel it would be great also if join actually made an the two objects continuous (at least an option) - which would remove the center point between the two lines following the simple example, but I'd imagine this may not be>simple< for every kind of join?

-Will
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 From:  Michael Gibson
744.4 In reply to 744.3 
> but I'd imagine this may not be>simple< for every kind of join?

Well, the problem is that it alters the shape... Right now when you use Join it will not sort of munge your curves around, the result you get after join will have the same shape as before.

So this would need to be an option. But Join is one of these commands that doesn't currently have any options, it just does its thing and bam! it's done... To add an option means making it stop and show some UI with a "Done" and "Cancel" button, this would have kind of a bad side effect of adding another step to the current regular use of Join.

I've thought about having a different variant of Join called "Merge" which would do this kind of thing (merge 2 segments into one single continuous segment), but I haven't quite figured out where to put it in the UI.

- Michael
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 From:  WillBellJr
744.5 In reply to 744.4 
Well it would be nice to have a merge command so hopefully you'll eventually figure out how you'd like to expand on your UI...

I'd think just add a "shelf" like you have for line and curve command options, however I noticed that you have a shelf for the curves and construct commands but nothing for the edit commands - they're all single function like you've mentioned.

Obviously this is your decision to make and we'll have to wait for you to decide how your UI is going to handle additional functionality such as this...

-Will
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 From:  Michael Gibson
744.6 In reply to 744.5 
Hi Will, well I'm certainly taking suggestions as well!

I'd like to put Merge on a "shelf" (I call these "Command sets" internally), since those really help keep the UI tidy.

But there's one additional complication in this case - a command that just goes "Bam" and immediately finishes after you press the button for it (like Join for example) doesn't quite work on a command set as smoothly as something that has additional steps that can be canceled.

You mentioned the draw comands - look at line for example. If you click on "Line" the command set appears, and the last one that you used will automatically start running. If you didn't want that one, it's no big deal, just click on the other one and the currently running one will cancel out and the other one will start running.

But that "auto-run" does not work with an immediately finishing command like Join because if it automatically ran it would finish up and be all done, before you could "switch over" to one of the different related commands in the set.

That means that immediately exiting commands like Join cannot Auto-run when they are in a command set. No auto-run means it would take 2 clicks to join something - one to open up the command set and then another one to click on Join to start it. The extra click for each join is the problem.

There are actually other areas that do this already - for example if you do a Boolean union (which is another immediate exit command), the next time you open up the Boolean set, it won't auto-run Union, you have to do a second click to launch it because of this same issue.

I don't worry so much about the one extra click for things that are not used so much in really rapid succession. Like with boolean union, you don't normally have to use it every few seconds or so. But Edit related stuff kind of falls more into that category, that's why there are no command sets in the Edit pallete, that keeps all the Edit stuff just one click to activate if that Palette is showing...

Anyway, those are some of the main issues... Eventuallly I may be forced to put Join into a command set in order to add more functionality like Merge, but I like to fight pretty hard for every saved click on frequently used things!

- Michael
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 From:  WillBellJr
744.7 In reply to 744.6 
Sometimes I do have to chuckle because it feels to me like you're "artificially" limiting yourself over the UI - people are so used to modelers now with all kinds of keyboard shortcuts, sticky keys, pie menus etc.

ZBrush has the whole world turned upside down as far as UI is concerned; people complained and complained about it - some ran to MudBox like it was a UI savior when it came to displacement / sculpting but when ZBrush 3 came out, people ran back to it, HAPPY that there was a new version with even more creative power irregardless of the user interface! (I've seen people say they were going to force themselves to use ZB3 just because of its power.)

So I don't know if MOI users need so much "hand holding" when it comes to the UI used to drive it.

Obviously I can appreciate your goal for a clean UI and the way it supports a pen as a standard is something you really need to be commended for - Silo is similarly lauded for having a clean UI so having that as a main goal is absolutely undstandable.

So these decisions are totally on you unless you ask your user base their opinions - I could see myself right-clicking the Join button for a merge, or left clicking for the normal join - but that's me.

However I'm still mostly using a mouse in MOI and I know right-clicking with a pen is not the most comfortable thing to do repeatedly. So with UI in mind that might not be the best option for getting Join and Merge on the same button.


I do believe however if the community was asked whether they'd like to have Merge now or wait till you determine how you'd like to further MOI's UI (v2.x), I know I'd like to have Merge in there now - even if it's just a keyboard shortcut!

Either way, MOI is a pleasure to use, you have a great program on your hands and as you see here everyday, we all LOVE IT!

-Will

EDITED: 10 Jul 2007 by WILLBELLJR

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 From:  Jesse
744.8 In reply to 744.7 
My experience is limited to jewelry design, but as Will mentioned, there are some work-arounds to avoid making poly-surfaces with seams,
when what you really want to make is a single seamless surface.

If you've drawn the perfect shape, but used segmented curves and ended up with seams, one way to fix them is to trace over the curves with a single
"through points" curve.

Regards,

Jesse
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 From:  rhumba
744.9 
Hi, thanks for all the replies! yeah Will and Jesse have got it. My issue is not with blend, but rather with sweep and revolve using 'joined' lines. Evidently joining two lines doesn't create a single segment curve, since the surfaces resulting from sweep and revolve have split lines. Blending or filleting the two edges so they are tangent before joining also doesn't solve the problem.

So the last point made by Jesse has it in a nutshell. Only by going over the line again with a 'through points' curve to make a single-segment curve can you make a non-split surface when using it in a sweep/revolve. But this seems a bit bizarre, surely there must be a better way to do it! As Michael says, the "deleting the point at the join" method will change the shape of the curve, but is a valid solution.
Anyway, the .3dm file I attach is a trivial example of a sweep and revolve using joined lines, which demonstrates this issue. I wouldn't bother looking at it really, nothing exciting!

You seem to be able to separate the joined lines afterwards, which indicates that the 'join' process is not quite what I thought it might be. Maybe you could keep join the way it is, but if the lines are tangent at the join it could ask you something like: "merge tangent lines?" which would mean an extra click is not always required.... but the more I think of it the less convinced I am by this! I'm really glad you're keeping the UI clean and well thought out Michael, it really shows.

Thanks for the suggestions everyone!
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 From:  jbshorty
744.10 
Actually, drawing a curve though points will not be exactly the same as the 2 joined curves. there can be huge differences. Because points are assigned varying weights, depending on what type of curve being drawn, and depending on it's proximity to the end of a curve. When you draw a new curve through points, the new points are not weighted in the same manner. and Moi has no system for adjusting point weights... so you will always have to decide what is an acceptable deviation for your model when joining and deleting a point, no matter how you attempt to clean it up...

jonah
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 From:  WillBellJr
744.11 In reply to 744.10 
Ummm, some bezier curves in MOI would be a yummy thing, fo-sho...

-Will
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 From:  jbshorty
744.12 
only if you want to develop really bad nurbs objects. Bezier curves are the devil... :)
shorty
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 From:  WillBellJr
744.13 In reply to 744.12 
okay, perhaps I just meant >handle bar< editors for the existing points - similar to Rhino...

-Will
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 From:  Jesse
744.14 In reply to 744.10 
Hi Jonah,

You made a good point about tracing a curve...it will not produce the exact same geometry, In my example, I was kind of sloppy..the curves don't match very well.

In Rhino, there will always be some deviation from the original if you match curves with "curvature" or "tangency" and merge or join them, or if you rebuild a segmented curve into a continuous curve, but depending on the number of control points you can live with, it's usually a very negligible deviation.

If you trace a segmented curve with enough control points in MoI, it will be, ( as they say) " close enough for government work" or good enough for jewelry design, in my case. :-)

-Jesse

EDITED: 11 Jul 2007 by JESSE

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 From:  jbshorty
744.15 
if you want to remove that crease without varying the curve too much, you can first join the curves, then add 3 control points on each segment at position very very close to the join point. Then delete the join point. Assuming it's a nurbs curve of no higher than degree 3, the effect will not extend past that 3rd new point...

jonah
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 From:  Michael Gibson
744.16 In reply to 744.13 
Hi Will,

> okay, perhaps I just meant >handle bar< editors for the existing points - similar to Rhino...

You mean like the HBar command in Rhino?

The main useful part of HBar is actually already built in to MoI - you can activate it by dragging on an unselected curve that has control points turned on.

For example - if you have this curve, if you click and drag from here:



You will get this dragging effect, same as if there was an HBar there and you were dragging the middle point of it:



This allows you to drag a point directly on the curve from where you dragged to a new location, you sort of grab a point directly on the curve with this mechanism. It's basically a way to manipulate several nearby control points all in one single motion, so it can be useful for kind of roughing out and making big changes to a shape.

This is a lot better than a dedicated command because it is always implicitly available just with a drag gesture on an unselected curve (if the curve is selected then you will drag the entire curve). HBar as a dedicated command is really quite awkward, you have to worry about firing up the command and repeating it a bunch of times... Also HBar in Rhino requires more clicks - you can't just click and drag on a portion of the curve, you have to click once to place the handlebar, and then click again on the handlebar to drag. This actually wasn't the case when I originally wrote HBar, it looks like that got a bit messed up in Rhino.

Re: full Bezier editor -

Doing a full bezier type editing system would tend to greatly exacerbate the original problem here about having multiple joined segments.

A Bezier editor creates curves that are made up of tons of little separate individual curves joined together into a long string. Each little piece is made up of 4 control points. It forces shared tangents by moving points together to be in a straight line between each little piece, but it generally does not produce shared curvature between each piece. So I'm not really planning on doing anything like that, it just does not create as high quality of smooth curves as the current NURBS system in MoI.

NURBS were essentially invented as a solution to this problem with chaining together lots of little individual Bezier curves! The mathematics are related, I mean NURBS builds on a lot of Bezier mathematics as a foundation, but it provides a way to have a smoother curve when you have more than 4 points.

Doing a Bezier style editor would be kind of taking a step backwards technology-wise...

- Michael
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 From:  WillBellJr
744.17 In reply to 744.16 
Absolutely WOW Michael!

(Please tell me, I'm NOT the only one that didn't know this could be done???!!)

Reminds me of the saying how when an elephant has been chained to a post long enough that you can remove the chains and it won't try to escape thinking it's still chained!


I've been so used to only being able to drag directly on the control points from all my other applications! I didn't even realize you could also drag directly on the curve!!

Yes, that IS so much better than HBars - again this is why MOI is so much BETTER; the UI is clean, simple and elegant!


Yes, I also understand that beziers aren't as clean as the curves we have now - knowing this additional trick for adjusting the curve certainly makes them unnecessary!

-Will

PS - Please tell me that this trick wasn't written down somewhere in the existing documentation?? Embarassing!

Boy I can't wait for the complete documentation on MOI when it's done!
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 From:  Michael Gibson
744.18 In reply to 744.17 
> PS - Please tell me that this trick wasn't written down somewhere in
> the existing documentation?? Embarassing!

:) Actually, it is covered in the primitive introductory documentation on the download page: http://moi3d.com/beta/MoI_Introduction.htm, it's mentioned under the notes for "Show pts".

But I think it is pretty easy to gloss over it there since there aren't any screenshots for it.

The screenshots or video captures that I will include with the proper documentation should help out quite a bit!

- Michael
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 From:  Jesse
744.19 In reply to 744.15 
-then add 3 control points

Hi Jonah,

I could very well be doing it wrong, but with the addition of the 6 new points, it drastically changed the shape of my curve...
maybe it works better if there is not a significant curvature? .could you post a before and after example?

Jesse
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 From:  Jesse
744.20 In reply to 744.18 
That's a very cool feature. Talk about embarrassing...
I remember trying it once, but then I completely forgot it...

What I need is a set of "tooltips" that automatically pops up when
I'm doing something the hard way and suggests a better method.:-)

Micheal,...maybe for version 9? ;-)

Jesse
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