How to do this? - Printable Version

How to do this? - Printable Version

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How to do this? - Dimitri - 03-14-2013

In what way you think someone may cut a spiral, as the one in the image below, to four -or more- equal parts with exact precision in Wings?

I am asking this because I have an idea for a new simple command which can be a very able aid for solving easily some such problems… but first I want to be sure that there is not an easy way of achieving such a thing with the already existent means…

(the cut in the image does not have any precision of course… it is made just for explaining visually the question)

I'll wait and see if anyone has an approach with Plain-old Wings3D. - ggaliens - 03-14-2013

I'll wait and see if anyone has an approach with Plain-old Wings3D.

RE: How to do this? - Dimitri - 03-14-2013

The idea I have is a very simple one... but let wait a little bit more, really... : - )

... ... ...

Well, as it seems there is no any answer… so, let explain the idea:

It is all about having a command similar to the ‘cut’ one we already have for cutting edges… but in this case for cutting loops in as many parts we want…

We do select a loop and click ‘divide loop’… there opens a dialogue which asks the number of parts we want to cut the loop… we do give the number and click ‘ok’: the selected loop is cut in as many equal parts we want.

Having such a command in our disposition the case with the spiral here is quite easy to manage: imagine that we want to cut it into two equal parts… we do select all the horizontal loops (as in the first image below)… we do ‘cut’ them to two parts (there appears a new vertice in the midst of each of them - as in the second image)… and then we do say ‘connect’ and create a vertical loop between the newly produced vertices (as in the third image). And, finally, there it is… we do have the spiral divided into two exactly equal parts. The same procedure may be followed in the cases where we may need cutting it in much more parts also, as is easily understandable.

All the needed thing is a ‘divide loop’ command…

RE: How to do this? - ggaliens - 03-14-2013

Right ... but now you need a usage case example(s) for how you would use this in practice.

I do like the idea itself ... but how you would use it for a real-world project ... a couple examples to share ?

RE: How to do this? - Dimitri - 03-14-2013

The very practical need of cutting such objects as spirals with such a precision is enough by itself for having such a command... but there can be many other uses of it also, having to do with producing new topology on various objects... especially the boolean ones. I have felt many times the need of such a command when trying to find ways to after edit boolean meshes.

It is a little bit difficult to illustrate the cases without having the command... but I will try to give some examples...

... ... ...

Here I have two examples showing some possible uses of such a command... they are about arraying on an object such irregular cylindrical shapes in a very accurate way (with equal intervals). I did make the loops using boolean impression. If we had the 'divide loop' command we could make a lot of such shapes and array them easily and accurately on the surface of the object...

(no need to say, producing such shapes on an object like this presupposes some very simple cutting-welding preliminary work in the first and last loop of the first and last shape of the whole array... for giving to the 'divide loop' tool to find exactly where it would place the cut vertices)

The tubes around the seams of the shapes, in the second image, are made with ML's 'tubes from loop paths' tool. As is easily understandable someone may do many things having such a 'loop divide' command as an aid...

... ... ...

Below are some further images illustrating the way such a ‘divide loop’ command may be used as a very effective aid in creating new topology on objects… I know, creating new topology may be a little bit tiring but if you look at all the existing apps’ ways of doing such things, you will see that it is a tiring somehow work in general. And, of course, all of them have a lot of tools for doing the work.

But, as I tried to show with my other similes, the need of having a ‘divide loop’ tool is openly evident… the contrary –not having such a tool- would be strange for a 3D modeling app as is Wings… To be honest, it is a so plain, as to its function, tool that there is no need even to discuss its necessity.

RE: How to do this? - Dimitri - 03-18-2013

Instead of making new posts I did update the last one in the thread... I do not know if the update is appearing as a new post on the list of the forum... so I am dropping this note here too...

RE: How to do this? - Dimitri - 04-24-2013

When I first mentioned the idea of finding the middle of a line in this thread I still had a question in my mind about the way this idea may be applied to loops: cutting a loop into two or many equal pieces is ok but… where exactly on the loop the newly created vertices would be located? So, I came to the conclusion that this issue can be solved by cutting the loop manually somewhere the user wants… so that the loop may stop being a loop anymore and become a plain line. And, therefore, the main reference point according to which the equal cuts will occur will be this manually created cut point-vertice.

Having a ‘cut line in the middle’ command is very important… despite its being a so simple idea it could constitute a basis of axial importance regarding retopo matters.

As is easily perceptible, it is just the same thing as the ‘cut’ command Wings always had… with the only difference that it can cut in equal parts whole long lines, not being restricted only to a line which stands between two vertices of a single polygon.

Mark, can we expect it? : - )

RE: How to do this? - ggaliens - 04-24-2013

I'm looking at the 142K jpg image ... and it scares me. It looks hard to make. I saw it and I ran away. Let me read some more here.

RE: How to do this? - Dimitri - 04-24-2013

: - )))

The command I propose has nothing to do with the image that scared you. The mentioned image is illustrating only a result of a whole process based on having such a command in your disposition. : - )

The 'cut line' command is very easy to understand as to its principle: you just are selecting some continuous edges (a line constituted from many edges in fact) on an object and then click on the ‘cut line’ command… there opens a tab where you choose the equal parts you want to divide the line… and, there, you have the result… just as it happens with the already existent ‘cut’ tool in the ‘edges’ mode… but this time instead of single edges it works on a line of edges...

It is just a line cutting command… nothing less, nothing more…

Below are two very simple images illustrating the whole thing... in the first image we have the case with the already existent 'cut edge' command. We do want to cut the selected edge to five equal parts and we do it with the known way. In the second image we have selected three continuous edges... that's to say a 'line' which we want to cut to five equal parts... and there is where the 'line cut' command is needed:

RE: How to do this? - Dimitri - 05-06-2013

Still waiting an answer... is it really difficult, as to its programming side, to implement such a command? I mean a command cutting a selected line in equal pieces? : - )