Hi Group,

Correct me if I am wrong but MoI cannot Loft using a point ?

Attached is a model with circular hole that is not planar, I would like to use the surface edge and a point to cap it solid with 'loft'

Rgds,

In the definition of loft: "Select a curve"
Is a point a curve? ;)
Do you want a cone?

Hi Paul,
How good of a patch do you need, does it have to be invisible where it joins the edges?

~Danny~

Frenchy:

In the definition of loft: "Select a curve"
Is a point a curve? ;)
Do you want a cone?

nope, I want a surface. This is possible in my other app which is why I ask ;-)

--

Danny:

It would be ideal but not critical mate, what do you have in mind ?

Rgds,

Paul, I was having a bit of a play around with 'network' but you could see the patch, then I discovered something with blend.
It's not a perfect patch, but almost invisible.

First I made this non planar surface with a hole in it.


Then draw these cross curves over the surface, which line up roughly through the center of the hole.


I discoverd you can split an edge using trim, the reason I have drawn 2 curves is because I produced 2 different results.
Pick the edge and use say the vertical line to trim with.


Found out by using this curve it split the edge into 3 pieces, which we don't want, when doing a blend, so use the horizontal curve for the trim and the result is that it splits the edge into 2 pieces (don't ask me why), this is just in this example you might have to experiment to see which curve splits the edge in 2.


Then use these 2 edges to create a blend G1 tangent and join the 2 surfaces and thats it, a fudged patch that doesn't look too bad :)


Edge Showing_____________________________________________________Edge Hidden


Anyhow it worked in this case, I don't know what you have modeled Paul, but it's worth a try and there's probably a 2 click method that someone more familiar with MoI will show, I'm still learning it.

Cheers
~Danny~

>>Found out by using this curve it split the edge into 3 pieces, which we don't want, when doing a blend, so use the horizontal curve for the trim and the result is that it splits the edge into 2 pieces (don't ask me why), this is just in this example you might have to experiment to see which curve splits the edge in 2.

The reason for that maybe because a circle starts when at 3 o'clock therefore if you split it vertically the edge goes into three, Michael ?

Many thanks for the great pics and method...never thought of that myself but will try tonight when i get home.

Best rgds,

Hi Paul, yeah currently there is no option to loft to a point, I have added that to the wishlist though.

There are a few different workarounds you can use to get that result though.

You can sweep to a point, so if you want to make something like a pyramid or custom cone shape, you can draw a vertical line and then use the "Pointy end" option in sweep. But that won't work so well for the kind of flat thing like you want here.

You can also select the edge curve, run Extrude on it, then turn on control points for the extruded surface and collapse the upper set of points down to a single location by using 2 repetitions of Transform/Align (one with vertical align and then one with horizontal align) - that will actually produce the same exact surface as lofting to a point would, let me know if you need more details on how this one works.

One other possibility is to turn on control points for your main surface and collapse the end of it in a similar way.

Another way that should work is to draw 4 lines radiating towards that point, then select the 4 lines and the surface edge and run Construct/Network to build a network surface there.

Another thing that can sometimes be ok is if you can split the edge up into 2 segments (you can split an edge into smaller edges by selecting it and running Edit/Trim and using the "Add trim points" option to pick a cutting point), then select the 2 edges and run Blend.


This is generally where you would want a "Patch" tool for filling in a hole like that - MoI does not currently have that tool (so this tends to be a rather awkward situation right now) but it is something that I want to add in the future as well.

- Michael

> The reason for that maybe because a circle starts when at 3 o'clock
> therefore if you split it vertically the edge goes into three, Michael ?

Yeah, the edge already has a "starting point", and if you cut it in 2 other locations that will dice it into 3 pieces.

But instead you can use Edit/Trim and the "Add trim points" option to place just a single splitting point, that will divide a closed edge into 2 pieces, between the start of the edge (which you can by the seam that runs along the surface) and the split point.

- Michael

> "Add trim points"

There you go, learning something new every day.

~Danny~

Hi Michael.

>>You can also select the edge curve, run Extrude on it, then turn on control points for the extruded surface and
>>collapse the upper set of points down to a single location by using 2 repetitions of Transform/Align (one with vertical
>>align and then one with horizontal align) - that will actually produce the same exact surface as lofting to a point would,
>>let me know if you need more details on how this one works

I would like to see how you do this please ?

>>But instead you can use Edit/Trim and the "Add trim points" option to place just a single splitting point, that will divide
>>a closed edge into 2 pieces, between the start of the edge (which you can by the seam that runs along the surface)
>>and the split point.

Yep, I see that now Michael (I am sometimes guilty of not reading the options within a cmd ) that was going to be my
next question relating to curves & edge curves, it is sometimes handy to know the 'start point' of a curve and the only way I
can see is to extrude a dummy surface from the curve and place a point on the seam ?. Can we see an addition point
cmd in the future OR when points are turned on make the start point look a little different ?

I actually think Danny's original idea and yours was the best and almost as good as patch !!

Rgds,

Hi Paul, the extrude + collapse thing goes like this:

Starting with a curve:



Extrude with caps turned off (or use Edit/Separate to break into individual surfaces so you can control point edit):



Now you can select it, and turn on its control points with Edit / Show pts. Switch to a side view and select the top set of points like this:




Now run the Transform / Align command. This allows you to line up objects or points. By default it is in horizontal alignment mode, which forces points to collapse down to a straight horizontal line. So if you pick a point in the middle of the object, the result will be this:



All the selected points were collapsed down to a horizontal line. Now run Transform / Align a second time, and switch the alignment option to be "Vert center" - this will now align everything to a vertical line, if you pick another point in the middle, that will cause the points to be fully collapsed together:



Once the points for one surface edge are fully collapsed down to the same spot, you can then drag that point to some location if you want.

That is the same surface that would be generated by a loft to a point (which is certainly more convenient and I would like to add that).


I do also want to figure out a way to show the start point of a curve, I just haven't quite figured out a good spot to place that yet - I'm going to be working on a kind of properties panel for selected objects in v2, and I want to figure out a place on that panel to pop up a menu with a bunch of additional stuff for an object, this could probably go there.

- Michael

Hi Micheal,

>> All the selected points were collapsed down to a horizontal line. Now run Transform / Align a second time, and switch the
>> alignment option to be "Vert center" - this will now align everything to a vertical line, if you pick another point in the middle,
>> that will cause the points to be fully collapsed together:

I see what you mean now....Thank You

I think this method would be fine for visual rendering later but stacked control points are never a nice thing when doing more
modeling using that surface ??.

>> I'm going to be working on a kind of properties panel for selected objects in v2, and I want to figure out a place on that panel
>> to pop up a menu with a bunch of additional stuff for an object, this could probably go there

Sounds good. May I ask will that show things like number of selected items, properties of item, validty etc ??

All the best,

Hi Paul,

> I think this method would be fine for visual rendering later
> but stacked control points are never a nice thing when doing
> more modeling using that surface ??.

Yeah you should avoid stacking points in the middle of a surface, but it is ok if it is an entire edge at the end of a surface. For instance a sphere has that same kind of collapsed-together edge in it, and Loft to a point will end up doing the same thing.


> Sounds good. May I ask will that show things like number
> of selected items, properties of item, validty etc ??

Yeah, hopefully a bunch of stuff like that, but probably focusing on properties at first.

- Michael

Loft to a point will end up with one cv in the middle no ?

As usual many thanks!

Rgds,

Hi Paul,

> Loft to a point will end up with one cv in the middle no ?

It'll look like that, but it is the same bunch of points all stacked up on top of each other. It won't be unusual for a NURBS modeler to treat a set of stacked up points on an edge as a single point in the UI when it comes to selecting or moving it, but in actuality it has the same structure as you see here.

In Rhino if you do the loft to a point, you can see the stacked up points by selecting the single point, and then use the "Smooth" command, that will slightly separate them and you can see the individual ones that way.

- Michael

Hi Michael - I gotcha now !

Many thanks for helping me understand this better from the MoI himself.

Rgds,