Hi Andrei,

> Hay Micahel, new method to to make revolve with loft! Revolve - 15 sec, Loft - 15 sec!!

Yup, actually that's the method that I had thought you were talking about originally, remember my previous post here? :
http://moi3d.com/forum/index.php?webtag=MOI&msg=6037.10

The main problem with that method is again accuracy - the revolve generates a shape that is 100% exactly a sphere in the top part where you have an arc profile.

The loft through different angled stations only approximates a sphere to some unspecific tolerance level, it's not an exact sphere shape.

It's important for some people's uses of MoI to have accuracy in what they generate.

The easiest way to generate an exact revolved shape that is 100% round and exactly matches one specific profile curve is to use Revolve to do it.

You also get a different kind of history updating when you use a loft through many profiles like you show there - the revolve lets you edit a single profile and the revolve will update as you tweak it, giving you a new exact revolve every time just from having drawn one single curve.

It just tends to be good in general to use the smallest number of curves to generate things, like in this case using only one profile curve and using revolve is just the most efficient way to do it, it only uses one curve. Being able to generate large amounts of your model from a small number of curves is basically the key thing that makes NURBS modeling powerful for mechanical shape design and different from sub-d modeling.

For Loft in addition to replicating the curves you also have to set the "Closed" option which is not on by default. And again, needing to use some sequence of steps and special options to generate a really basic shape like this is a barrier for someone who is learning MoI to be able to create a simple shape like this...

- Michael

I know Michael, you are right I do not pretend to replace revolve with loft)
Just got and idea about this method, and yes you show this method before I forget it)
I just fun of Loft you know))) One question why when normal styly selected, Exact and Point do not work?

Hi Andrei,

> One question why when normal styly selected, Exact and Point do not work?

They work fine for me over here... If you have an example where they don't work can you please post the 3DM file for it so I can take a look?

- Michael

This one.

Just an idea :)

Does it possible to have as option something who write the functions, ShortCuts, Mouseclicks... used in a corner of the screen?

Because in the last Video of Samardac, that was be useful when you replay in slowtime! ;)

Works fine for me! With any options!
Here not closed but works fine also closed!



remember this ;)

Hi Andrei, it seems to be working fine there - maybe the thing you weren't expecting is that it works on a per-segment basis, so for instance if you put in # Points mode and give that 10 points, it will be 10 sample points used for every segment of the loft, like the arc piece, line pieces, etc... Also the min number of points is 4 if you try to put in less than 4 per segment it will still use 4 instead.

If you would like for the loft to be treated as one single surface rather than as a segmented one, run Rebuild on the curves before doing the loft so that the curves are only single segment curves instead of made up of multiple segments.

Does that explain what you're seeing?

- Michael

Hi Pilou,

> Does it possible to have as option something who write the functions,
> ShortCuts, Mouseclicks... used in a corner of the screen?

I think that some types of screen capture software can do that for you, for example Camtasia can make a red circle appear around the mouse when clicks happen and it's also possible to make labels show for keyboard shortcuts that are used, here is a demo video on how to do that: http://www.screencast.com/t/Sz0jxaa6

So it's probably not something that I'd try to do directly in MoI since a good screen capture program can already handle it...

- Michael

Yep michael I understand this concept per segment, I noticed before that after rebuild it work, now everything is clear!
But tell me pleas conception about exact in this case. I see it not produce exact amount of points.

Pilou, I mean Points and Exact dose not work) Loft work good)

Red rocket)))

Michael,
>I think that some types of screen capture software can do that for you.
I think it will not say more to people what shortcuts I use. I think Pilou wanted so see commands?

Pilou if you want to see my shortcuts you can find them here: http://moi3d.com/forum/index.php?webtag=MOI&msg=5948.1

Hey Andrei,
I think you would get a kick out of the cross section command if you havnt discovered that yet. You can find it and get info here:

http://kyticka.webzdarma.cz/3d/moi/#CrossSection

Burr

Hi Andrei - "Exact" does not so much actually mean "exact number of points" - it means "exact shapes". In exact mode profiles are made compatible with one another by knot insertion so that the shape of the loft surface will go exactly through each profile but the end surface inherits the combinations of all point and knot structures of every curve, so usually the final surface will have more points on it than every input curve.

If all the curves are exact copies of one another then they should merge together easily though and you do get the same number of points in the surface in that case.

But because the loft is internally generated as a single big surface before it's split at creases, all pieces of the loft will get "degree elevated" to the highest degree segment, so in this case the arc is degree 2 so the linear areas get degree elevated to degree 2 as well and that's why they have an additional point in those areas.

Also in addition to that when you turn on control points for arc or circle curves what you actually see are not the control points of the exact arc or circle but instead the control points of a rebuilt version of the arc or circle, that's because an exact NURBS circle or arc is itself made up of quadrants that do not deform very well by control point manipulation, so if you edit an arc's control point it automatically switches it into a smooth rebuilt version of it so that it doesn't kind of split apart into 2 arcs divided by some internal point. But in the generated sphere surface you're seeing the direct surface control points in that case. If you pull some of those sphere fragment control points around you'll see some of the splitting apart that I'm referring to, that happens when a surface or a curve has a "fully multiple knot" in it, it sort of means the curve or surface has another kind of internal segmentation in it.

Hope this helps explain some of the additional details.


- Michael

Very complicated, I think it's very low level for me. One thing I understand is - If all the curves are exact copies of one another then they should merge together easily though and you do get the same number of points in the surface in that case. In all other ways exact does not mean exact amount of points)) And understand a bit about circles)))
Thanx)

Thanx BurrMan,
Really good command, I think I'll use it, did not know about it, thank you very much!

Hi Andrei,

> Very complicated, I think it's very low level for me.

As I've mentioned many times before, really if you want to do direct surface point modification a sub-d modeling toolset tends to be a better fit for that than NURBS modeling.

Some of the things that give accuracy to NURBS modeling do not lend themselves well to squishing surfaces around. Some problems like internal segmentation on circles/arcs/spheres can be avoided though by doing a rebuild on it.

- Michael

Hello,

Interestingly this is a very good illustration why you wouldn't use loft (left) as a replacement for a more appropriate tool for the task, revolve (right). Same set of curves, just ran the commands. A curvature analysis is shown in the picture. Poor surface quality in the lofted shape which could lead to further problems as it is modified. No such problems with the revolved shape.

@Andreï
As fan of Loft maybe this script can interest you ;)
http://moiscript.weebly.com/deacuteplacer-des-objets.html

link of script is on top page! MoveSlicetoPoint
Interesting when you have a lot of slices

Thank you Pilou, intersting script, looks like I'll use it.

Michael.

While using the Loose option in the Loft tool I wondered if a slider control would be a worthy addition to let the degree of 'looseness' be tweaked to one's liking?


Martin.