Hey guys,

i need your expertise


What is the fastest way, to put lines exactly onto the surface of a 3d object with MoI 3d ?

Is there any solution ?

Attached you can find a smiley, which "flows" over a cone.. The aim is, to put the smiley exactly onto the cone,

which means that the lines must be bend in the right angle. I tried many stuff, but it is like impossible for me :)

Thank you for your help in advance !

Guess this is what you mean: http://moi3d.com/2.0/docs/moi_command_reference7.htm#project

I would use the FLOW command, with a surface which is the same as the target, "unwrapped," for a developable target.

- Brian

Now to try it...
Looking into unwrapping cones now...:-)

Hi sosodef, yeah you probably want to use Transform > Deform > Flow for a case like that. Flow is a new tool for v3, see here for an example video: http://www.screencast.com/t/3rzeZvqB9z

You can also use Construct > Curve > Project for a different method, that's more like beaming it on like a movie projector and Flow is more like applying a texture to the unwrapped surface. For something that's going onto a relatively tightly bent area for its size you probably want Flow since projection will have a lot of deformation in the areas where the surface is steep in relation to the projection plane.

- Michael

Hi sosodef, I've attached here an example result using Transform > Deform > Flow.

To prepare for doing the Flow you need to create a plane which will be used as the base surface in the flow. Then the flow works basically like applying texture mapping, the geometry goes from the base plane onto to the target surface.

- Michael

Thanx Michael, never think about difference between project and flow, flow really makes "projection" more correct.

Thank you Michael, Deform -> Flow worked perfectly for me !

But another problem occurs...

i need to sweep a circle over "projected" lines... If I do so, the ends look, messy, because the sweep goes over the edge of the yellow lines ...!

If i choose the option pointy start or pointy end it looks almost like how it shoud do, but in this case.. the start/end gets smaller, which shouldn´t do !

Can you help me out once again, please ?

Thank you !

Hi sosodef, usually 3D curved paths will not be able to have ends mitered on them. The mitering involves doing an extension and intersection between the extended sweeps and when things are all bending around in 3D rather than planar usually there will not be a clean intersection produced from that mechanism.

You can get mitered corners on planar paths though. So one method would be to do the sweeps before doing the flow and do the flow on the sweep as well.

The other thing you could do would be to make your paths meet each other smoothly instead of coming to a slight sharp corner. If the path is smooth then the sweep pieces will meet up directly with one another.

To make the paths smooth you could trim away a small area around the current slightly sharp corner junctures where you are having problems, then use Construct > Blend to put in a smooth segment to fill in the empty space that you trimmed away.

- Michael

Is there a way to draw or project a closed curve on a surface without it adding more points ?

Both "flow" (projection option) and "project" add more points to the curve.

I don't want to add more points as I am using the curve as a basis for lofting which works best if all curves have equal number of points.

I've also tried drawing a curve in the right ortho view on a curved surface with osnap "on surface" and that doesn't work, it just draws it on the xy axis


EDIT: just figured it out you have to draw you curves in perspective view with osnap "on surface". The osnap doesn't work in ortho views which is a pity because when your trying to draw stuff accurately you mostly working in the ortho view or cplane views.

Hi Kevin,

> Is there a way to draw or project a closed curve on a surface without it adding more points ?

If you use projection it calculates a result curve to within tolerance - if you only used the same control points as the original curve the curve would not fully be on the surface, the spots in between control points would sag away from it.

I do want to make it possible to use project when control points are selected rather than the curve itself selected to only move control points around but that does not work yet.


> The osnap doesn't work in ortho views which is a pity because when your trying
> to draw stuff accurately you mostly working in the ortho view or cplane views.

Ortho views are more focused on drawing planar shapes aligned to that view, the 3D view allows you to more freely draw things stuck onto surfaces.

There are settings you can adjust to alter this behavior, if you go to Options > Snaps > Object snap options > "Project to plane in ortho views" and turn that off, that will prevent the planarizing behavior. The planarizing mechanism is where things like curves or polylines keep newly picked points on a plane through the previous picked point that is parallel to the view's cplane.

Then if you want "On surface" snap to work in ortho views, there is a setting in moi.ini where you can enable that, under [Drawing Aids] :


[Drawing Aids]
<....>
DisableOnSrfInOrtho=y


Switch that to =n and then you should get the snap behavior that you want.

Just be aware that with those settings changed like that, drawing lines and curves in one of the ortho views will no longer necessarily generate a result that is planar to that ortho view anymore.


- Michael

Ok, thanks Michael for offering some potential workarounds.

>if you go to Options > Snaps > Object snap options > "Project to plane in ortho views" and turn that off, that will prevent the planarizing behavior.

Unfortunately that doesn't work. It still draws a planar shape on the xy axis


>DisableOnSrfInOrtho=y
>Switch that to =n and then you should get the snap behavior that you want.
That doesn't work either.

I restarted Moi after making these modifications, and it still doesn't draw on the surface in ortho view. It just draws on the xy axis. In my all my tests I disabled all osnaps except "on" and "on surface"

Is it a bug ?

Hi Kevin, I tested both of those settings before I posted to make sure they did what I thought, and I just tested them another time right now and they're working as expected...

Did you possibly try to edit the moi.ini file while MoI was still running? That doesn't work very well since MoI writes out settings to moi.ini when it shuts down, so if you edit it while MoI is still open it's easy for your changes to be overwritten.

So please do the following - make sure you have only one instance of MoI running.

Go to Options > Snaps > Object snap options and uncheck "Project to plane in ortho views" (the second one from the top).

Now go to Options > General and push the "Edit .ini file" button. MoI will now close and moi.ini should come up for editing. You should not have any other running instances of MoI at this point.

Inside the .ini file search for DisableOnSrfInOrtho and change it to DisableOnSrfInOrtho=n

Maybe you have also run into some additional thing with grid snap, there is an additional setting for whether on surface in ortho views is enabled when grid snap is on, if you want that as well then set DisableOnSrfInOrthoWhenGridSnap=n as well.

I tested this all again right now and it's all working as expected, if you are still running into problems I guess I'll need some more detailed description. When you say "on the xy axis" do you mean snaps on the x and y axis lines, or are you talking about on the xy plane? There is an axis snap feature that snaps points onto the x or y axis lines, if you do not want that to happen turn off the Axis object snap type.

- Michael

Michael thanks !

Working perfectly now. I will use this feature a lot in my work so really handy to know I can do this. Up to this point of been projecting the curve, then rebuild, then delete points to match the same amount of points in my other loft curves. Quite tedious stuff.

I don't suppose there is a script that could toggle all these features off and on as I need ?

It must have not worked before because I had the ini file open on screen while closing Moi and reopening although I did save the ini file.

>When you say "on the xy axis" do you mean snaps on the x and y axis lines, or are you talking about on the xy plane?
xy plane

Hi Kevin, I'm glad it's working ok for you now!


> I don't suppose there is a script that could toggle all these features off and on as I need ?

It is possible to do a script for the checkbox setting, but the other 2 settings are not currently exposed to scripts so they can only be adjusted for now in moi.ini and not by a script.

- Michael

Ok, thanks

I think I will able to do most of drawing curves on surfaces & tweaking them in the perspective viewport and keep on eye on who it looks in the ortho view.

But if that proves tricky at least I now have this workaround.

> [Drawing Aids]
> DisableOnSrfInOrtho=y
> Switch that to =n and then you should get the snap behavior that you want.

That would be nice to be able to toggle this behaviour with a shortcut. Can I temporarily change program options during runtime? By 'temporarily' I mean, options are changed, but not saved.

Hi Ditto,

> Can I temporarily change program options during runtime?
> By 'temporarily' I mean, options are changed, but not saved.

Your current settings are saved by MoI into moi.ini at exit time, so basically no there isn't any way to change a setting that's stored in moi.ini and not have it saved when you close the program.

- Michael

Hi Ditto,

> Can I temporarily change program options during runtime?
> By 'temporarily' I mean, options are changed, but not saved.

One thing you can do though if you want to be able to easily revert back to some saved group of settings is to make a backup copy of your moi.ini file, then when you exit MoI copy the backup copy of it over onto the main moi.ini file again. That will then restore all settings.

You can find out where your moi.ini file is located by going to Options > General and push the "Edit .ini file" button, the dialog that pops up will tell you where the file is located.

- Michael

Hi Michael,

Thanks for the replies. So if I can't temporarily change options, can I change them from within a running MoI instance? In this example, there is this DisableOnSrfInOrtho option in the ini-file. Can I modify this from within MoI this without editing the ini-file? Using a shortcut, for example.

Thanks!
Ditto

Hi Ditto,

> So if I can't temporarily change options, can I change them from within a running MoI instance?

With most settings you can do that by running a script. But these particular settings are not currently exposed to script, they're only read from the .ini file and there isn't any access to them from script so there is not currently any way of changing these particular settings from within a running MoI instance.


> In this example, there is this DisableOnSrfInOrtho option in the ini-file. Can I modify this from within
> MoI this without editing the ini-file? Using a shortcut, for example.

Sorry, no not this particular setting, it has not been set up to be accessible to scripts.


- Michael