Hey cool Pilou :)

Are you really using this color scheme in MoI ? Oo

< Are you really using this color scheme in MoI ?
No it's just a colorisation in 2D prog but why not if a colorisation system was embeded in the UI :)

Hi Pilou,

>>Easy isn't it ;)

Yes, it can be. I like how you have shown progression so others can follow.


Hi rampackwobble

>>I am only just starting to realise how usefull the sweep tool is.

Sweeping can give some very interest shapes. You should also notice that you can add scaling rails to the sweep, which can be very interesting, but can cause some problems(as not everything is possible in a scale/control that is viable) so some caution, and expect some unexpected results if used.

I'd like to see a good explanation and example of what scaling rails do. Plus when and how to use them.

Ed

Hi Ed...

As starting, have you look at this video http://moi3d.com/1.0/docs/Pod.wmv ?

- Anis

Nice Hat! I'm hoping to become proficient with MoI as you. I have also been trying to do Sweeps and the rail thing.

I beleive it's the same as another modeler "Carrara" I use. creates a "Spline object" which has "Symmetry" lines for manipulation.



Seems as though the Rails option (Two Rails) represent the Extrusion path in the 2 planes? (Carraras shows 1 symmetrical pink line) and the "Scaling rail" represents the "Blue and Green" symmetry paths"?

I'v been trying to figure out the 2nd rail option.

From Carrara, The scaling rail is the one with 2 "Plane" options, and if you need to change the extrusion path (the rail) you would add a "Cross section" and new rail and continue. Have I equated the 2 the same?

I'm not getting the result with the second sweep rail I thought and trying to adjust as needed!

Any thoughts? (did my question make sense?)

Thanks Burr

Hi Ed, yup that Pod video has a good example on a scaling rail in action.

The basic idea is that when you normally do a sweep of something like a circle along a rail path, the result will be a very evenly sized tube.

That's great if you want something very evenly sized, but if you want something that flares out at the end or swells up or pinches down in the middle a bit, something other than just a very even tube, then that's when a scaling rail can help to make that kind of a customized tube shape.

You can also use more than one profile cross-section curve in the sweep to get a kind of similar result, like for example use 5 different circle profiles each of a different radius, as the profiles for the sweep and it will make a kind of bulgy tube as well.

But if you find yourself using quite a whole bunch of profiles like that, it is a good idea to switch to using a scaling rail instead, because it basically controls the flare of the sweep with one "side" profile curve (which is much easier to edit and tweak) rather than a whole bunch of individual circles of different sizes.

Here is a visual example:



The basic sweep there produced a very sort of "normal" tube, then applying the scaling rail in the last image shows how it stretches the sweep out until it matches that additional shape, making a bulge in the middle and flaring out at the end.

You can also use it in spots where you don't need such a dramatic flare or bulge bug still want some control over changing the profile gradually over the course of the sweep.

Please let me know if you need some more examples, that Pod video is a pretty good spot to see it though.

- Michael

Hi Burr,

> I'm not getting the result with the second sweep rail I thought
> and trying to adjust as needed!

Please post the .3dm model file with your curves in it that you are trying to sweep, that will really help me to see what problem you are running into and give you some advice on what to do differently.

I'm not really familiar with that Carrara tool, but it looks to be different from a sweep - a sweep in MoI is not really constrained to work relative to the x/y/z planes only, it follows the rail curves.

So that allows for stuff like this for example:



I'm not sure if that Carrara tool is going to be able to do stuff like that, if it is focused very much on editing from a side plane projection it probably will have some difficulty when a path wants to kind of loop around more freely...


To do a shape more like what you are showing there in MoI you would probably draw cross sections and then use loft, something like this:



It is possible to use sweep to do something similar with a straight line as the sweep rail, but Loft would probably be more typical for something like that.

- Michael

[EDIT] Just saw a reply as I posted, May answer my question.[EDIT]

Here I am trying to do a fishing led. I create the shape I want but need the neck to narrow in only one plane. this model has symmetrical polygone on both ends.

If anyone can point me in the right direction I'd much ablidge. Was trying to fool with (demo from pod) adding other profiles as it goes. I think this is right but still trying to squish my polygone (On the small end only, and for only 1/8 the length) asymmetricaly. How would I do this? (Scale in x/y only?)

Sorry it's so newb. Trying to switch my brain.

Thanks again,
Burr

Hi Burr, if I understand you correctly try switching the "Maintain height" option to be on (checked) for your sweep.

That's one of the options that will show up in the upper-right area of the screen when you are doing your sweep.

When "Maintain height" is on, it will stretch things only in the one direction towards the scaling rail which I think is what you are asking about?

When "Maintain height" is off, things will instead get scaled in a uniform way, getting bigger or smaller in all directions instead of just in the direction towards the scaling rail.

In your case you have the scaling rail running along the top of the object, if you wanted the squishing to be more lateral instead of vertical, then switch ot the right-side view and rotate your scaling rail 90 degrees so it is on the side of the object that you want the stretching to go in.

Please let me know if this doesn't make sense!

- Michael

Michael,
The Maintain height check does indeed produce the "squish" I am looking for, though, I want the symmetrical path for 7/8 the length and the "squish" for the last 1/8.

Heres a picture of the end result I want.

Hi Burr,

> though, I want the symmetrical path for 7/8 the length and the
> "squish" for the last 1/8.

There isn't any way to do maintain height only for just a portion of the sweep, it's either on for the whole sweep or off for the whole sweep.

But you could do the sweep in 2 portions if you want, with different options set for each portion, will that do what you need?

I'm sorry I can't quite follow what you want from those images, they're kind of dark. Is there any way you can describe it a bit more?

It may be possible for the case you are talking about here where you want shifts in behavior at different spots in the rail, that using multiple profiles would be a better way to go than using a scaling rail, but I'm still just not quite sure what your desired end result is though.

- Michael

Seems probably loft is more what I need. can I make my Polygon asymmetrical for the last inch? Probably more the newb question is how. Thanks for your time.

DO these show the difference in neck width?

Mutiple profiles and Lofting is my answer. Thanks again.

I'll post a new thread for my basic questions on "How to draw" for dummies.

Burr

Hi Burr,

> Mutiple profiles and Lofting is my answer. Thanks again.

You're welcome - sorry I didn't understand sooner.

Yeah if your shape is kind of following a straight line, then yeah sweep is probably not really very necessary.

However, sweep and loft are similar in some aspects, like you can also use multiple profiles for Sweep in the same way that you used them in Loft, it's just that sweep also uses a kind of "spinal column" rail to follow along.

- Michael

Is there somewhere that would tell me How you would do sweep in 2 portions with diiferent params for each?
Is this the second rail thing? Or, how is the second rail used?

I think this is what the original thread was getting at and I would like to know also.
Thanks.

Also, I think this is what was confusing me before. In the Carrara program, they have a sweeping tool that does the scaling rail, also with symmetry (your keep height check) and they ALSO do the cross-section lofting in the same area. Yours is split into 2. (yet dual functionality in both. sweet!)

Hi Burr,

> Is there somewhere that would tell me How you would do sweep in
> 2 portions with diiferent params for each?

Sorry I didn't describe that better earlier - to do that you would need to cut the rail curve into 2 pieces.

Then you would repeat the sweep twice, the first time picking one piece of the original rail, and then doing a second sweep using the remaining portion.

To cut the rail, select it and then run the Edit/Trim command. It will prompt you for "Select cutting objects". If you have a line or something that crosses the rail you can select it as the cutting object here, or you can also click the "Add trim points" button, which will then let you click a point on the curve to use that point as the split location.

After you have finished picking the cutting objects or cutting points, the Trim command will prompt you to "Select pieces to remove or push Done to keep all" - here just push Done (or right-click inside a viewport which is a shortcut for Done) because you want to keep all the cut-up pieces and not discard any.

So after doing that your sweep rail will now be cut into 2 curve pieces. Do sweep twice, using a different piece for each sweep and that way you can use different settings for each time you run the sweep command.

Please let me know if this doesn't make sense and I can make some illustrations.

- Michael

Very Clear, No need to illustrate this. Please when you have time, illustrate the "2 rails" sweep. I'm thinking this equates a way in my old modeler and want to be sure. ie;

Part on wall plane z.

first rail on wall plane x.

second rail on wall plane y.

???

When you have time.

I also posted a thread on our previous discussion here regarding sweeps and lofts. Please review my results!

Thanks,
Burr

http://moi3d.com/1.0/docs/moi_command_reference7.htm#sweep
(scroll)
PS You can select any numbers of profil before to choose the 2 rails
You are not obliged to put your profils on the rails! (they must be in the same plan)