Hi NightCabbage - those kinds of manipulations that you are asking about would be the kind of stuff that you would do in a polygon modeler.

MoI's geometry system is much different than polygons - it uses a system called NURBS solids and one of the side effects of this is that you can't generally just grab any edge that you see and pull it around.

Often times the edges that you see may be "trim edges" and not necessarily the edges of the underlying surfaces.

Please see this FAQ answer which has some illustrations and explanations of how trim curves and "underlying surfaces" work with this geometry system.

Even though this system does not generally allow for pulling edges around, it has other benefits - it's pretty much the reason why booleans work a lot better on NURBS solid modelers than in polygon modelers, because when objects cut one another the underlying surfaces stay the same and only new trim curves are created on them. In a polygon modeler where edges are easily pulled around, when you do booleans it has to fragment things up into a bunch of smaller little surfaces which tends to make things messy for polygon booleans.


So usually if you wanted to make a scaled cube, you would do more of a "construction" way to do it in MoI rather than "squish a different object" method - the construction method is to draw 2 rectangles of the sizes you need and then use Loft between them to build your shape.

That's generally the method that you use for building objects in MoI, you work more on forming and shaping some profile curves, then construct your object from that, rather than taking something like a cube and squishing it around into a different shape which is common in polygon modelers.

MoI's method of "construct from profiles" tends to lend itself very well for man-made objects which tend to be well defined by profile curves. The "squish edges and points around" kind of method of a polygon modeler tends to be good for more organic things like characters, monsters, faces, stuff like that.

So which method you use can depend on what kind of model you're trying to build.

If you're trying to squish things around a lot, then you probably wouldn't use MoI for that, you'd use a polygon modeler instead.

Hope this helps explain some stuff!

- Michael

So after having said all of that, in the case of a simple box you can actually squish that around in MoI by using Edit/Show pts to turn on control points, and then select some of the points and use tools like Scale or whatever to edit them.

A box is a special case though, since its edges happen to align with the edges of the underlying surfaces.

Once you get something more complex (including doing a boolean on the box), then that won't work anymore unless you break things apart into individual surfaces like Danny mentions above. Again check that FAQ topic for some more details on this.

- Michael

"Show Points" and then select the 4 points of the top surface, then in the upper right corner where the entity summary is, click on the size label and then type the new size in there.

Usually "Solids" are not going to edit in this way. You need to create it the Shape you want. Danny did a great little tute on creating a draft angle using "Chamfer with 2 distances".

"tan(20)*Distance"

I'll see if I can find the link and post it.

Burr, you have to remember that the new guy's trying MoI out are using V1.1, you know, the version that shows up in your 'Add and Remove Programs' as rarely used :)

Cheers

Heh, yeah sorry - using the old version :)

But hey I'm really enjoying it - so I'll probably buy it and then I can switch to the new version, which sounds like it has many improvements.

Most of the 3d software I've used is polygon based, but recently I've been branching out, because I generally don't like the flow of poly-based modelling.

There are so many choices around these days...

3ds max / Maya
Modo
ZBrush / Mudbox
etc.

But I really like the idea of creating objects like Moi does - I've been waiting for someone to make a program like this for years :)
(3ds max does nurbs but nowhere near as good as Moi)

Sorry if I sounded completely green (I am fairly inexperienced in 3d modelling though).
My background is in programming, web design and game design.
I'm not a skilled artist, but hope to get some skills in this area - it's about time.

Thank you for coming up with a couple of solutions for my problem! I feel much better now :)

Highly looking forward to trying out this new version...

Hmm ok, new problem, but I'll keep it in my little thread so as to not clog up the forum with silly problems and questions :P

So I've created a cube out of lines this time.

12 lines forming a 2x2x2 cube.

Now I'm trying to join them together. But for some reason only some of them are joining, and the rest are not.

For example, if I join the top 4 edges together, that works fine - I get a nice little flat box.

Then I can't join any other edges to this box.

And if I just select all 12 edges, and hit Join (which would be the ideal way of doing it) - it just seems to join random edges together, leaving the others unjoined.

It looks as though it only likes joining edges on the same plane - but that's just a guess.

Perhaps this is fixed in the new version? Or maybe I'm doing something wrong?

Thanks :)

Hi NightCabbage - re: Join for curves

Yeah join for curves is meant to join segments that touch end to end into a single large (possibly closed) loop.

For curve joining to work properly, you should only have 2 segments touch each other at any one point. You wouldn't use curve joining on a branching structure like 12 lines arranged in a cube wireframe.

Instead of trying to make all those individual line segments, the way that you would generally make a sloped cube in MoI would be to have 2 rectangles, like this:



Then select them both and run Construct / Loft to build the result like this:



You generally try to focus on making some curves that are cross-section profiles like that rather than trying to make a branching wireframe structure like you were talking about with the 12 individual lines.

Hope that helps!

Also have you already seen the video tutorials which are available here:
http://moi3d.com/1.0/docs/tutorials.htm

If not, those are worth checking out, they go over all the steps to build some simple example models.

- Michael

Oh, of course! That makes sense :)

It's funny how I seem to have a different perspective of how things could be done in a 3d environment... bit of a learning curve for me - heh!

Hi NightCabbage,

> It's funny how I seem to have a different perspective of
> how things could be done in a 3d environment...

Actually the way that you were talking about doing it does fit into a polygon modeling type of system which is a different kind of 3d environment than MoI's method.

There are actually a lot of different possible methods out there for building 3D models.

- Michael

Hey Cabbage,
Also remember that it makes it alot easier if you have a question to post a file along with it. It helps to eliminate some confusion about a particular model or modeling question.

Good luck.

Danny,

Oh Yeah. thanks for reminding me.

I'm back to folding plans now. ;)

Ok, so I've been palying with Moi a bit today, and aside from having great fun, I'm actually getting it to make the stuff I want :)

But I still regularly come up with the problem of wanting to just change a particular line/curve of an object...

And I'm wondering why it isn't possible to do this (without separating the object)?

Example 1:



The above is one solid object.

However, during the making of the object, a circle (blue colour) was cut into the surface (yellow colour).
(I coloured the circle blue myself, by the way lol - don't have V2 just yet hehe)

Is there any reason why I can't just delete that blue circle, and have the yellow surface without that circular hole?

Example 2:



Once again, the above is one solid object.

But what if I wanted to change the shape of the exhaust?
Or perhaps I want to move the whole exhaust to a different place on that flat surface?

For my usage, this is the number one "most wanted feature" :)

Begin able to edit existing shapes by their internal components (lines and surfaces - though of course the surfaces are created automatically by the lines, but the surfaces should control the surrounding lines)

What do you think?

-EDIT-

Oh and I've read the FAQ but still think that this feature would be worth implementing / figuring out.

Hi NightCabbage,

> Is there any reason why I can't just delete that blue
> circle, and have the yellow surface without that circular
> hole?

Actually you can do that - if that blue circle is a circular disk type surface, select it and delete it first, which will leave an empty hole. Then you can select the remaining edge in the yellow surface to "untrim" it and recover the underlying surface in that spot.

Here is one post that describes untrimming in more detail:
http://moi3d.com/forum/index.php?webtag=MOI&msg=444.4

Also here is a more complex mini tutorial that talks about using untrimming and re-trimming to repair an object that had a boolean done to it in an incorrect location:
http://www.moi3d.com/forum/index.php?webtag=MOI&msg=446.17


> Once again, the above is one solid object.
>
> But what if I wanted to change the shape of the exhaust?

You normally would just delete those faces that make up the exhaust and then construct a new one there instead.


> Or perhaps I want to move the whole exhaust to a different
> place on that flat surface?

You can basically detach the exhaust surfaces from the rest of the object by selecting those faces that make it up, and then using Edit/Separate. That makes those faces into an independent object which you can move somewhere else.

There's an object repair tutorial that goes into much more detail about this which is available here:
http://moi3d.com/forum/index.php?webtag=MOI&msg=446.17


> Begin able to edit existing shapes by their internal
> components (lines and surfaces - though of course the
> surfaces are created automatically by the lines, but the
> surfaces should control the surrounding lines)

In the future I would like to make it possible to edit the model by moving edges around, but the way NURBS are structured it is not really an easy task to make that happen. It involves things like merging trimming boundaries, extending surfaces, stuff like that. That's because with a NURBS solid the edges that you see are not necessarily the edges of the "underlying surfaces", they may be trim curves which are just on the surface but not necessarily aligned with the surface's natural edge, which is a much different structure than how polygon meshes work.

There are some other NURBS modeling systems out there that have refined that kind of editing to a greater degree, one example is SpaceClaim, if that kind of editing is a big concern for you, you might want to check it out.

- Michael

"There are some other NURBS modeling systems out there that have refined that kind of editing to a greater degree, one example is SpaceClaim, if that kind of editing is a big concern for you, you might want to check it out."

Ah, but I really like your work, Michael, so I think I'll stick with MoI :)

I do think that the ability of being able to move things around like that would be a great asset to the program, as many professionals out there are used to this kind of feature in poly modellers, and having it would be a great draw-card to your program.

"un-trimming"

Oh, that was easy - I thought I'd already tried pressing delete on the edge at least a dozen times?? lol
It's pretty intuitive, so that's good (no idea why it didn't work before!)

-EDIT-

"In future versions I should be able to add more options for doing this kind of thing more automatically, for instance it could eventually be possible to enable dragging the hole around without erasing it first, or using history to change the size of the object being booleaned. But for V1 these won't be ready so the "erase hole" technique is what will work for right now."

Hehe, this gives me hope that you have it planned! :)

Hi NightCabbage,

> I do think that the ability of being able to move things
> around like that would be a great asset to the program,
> as many professionals out there are used to this kind of
> feature in poly modellers, and having it would be a great
> draw-card to your program.

Yup, I definitely agree!

The reason why it hasn't been added yet is not because I don't think it would be a good and useful feature, but just because it is not an easy thing to implement and will take some hard work to enable it.

- Michael

Hi NightCabbage,

> It's pretty intuitive, so that's good (no idea why it didn't work before!)

Well, if you select the edge while you still have that blue surface in place, it won't delete. Untrim only works on edges that are not connected to other things, so you have to delete the blue surface first before having an open hole there... Maybe that was what you ran into?

- Michael

Quite possibly :)

So general rule:

You can always delete surfaces, but you can only delete lines that don't have any dependant objects (like a surface).

Hi NightCabbage, yes that is correct.

Also to delete edges you need to select the entire loop that forms the trimming boundary. Like for example if you have a square hole with 4 edge making up the hole you have to select all 4 of those edges to delete, not just one of them.

- Michael