difficult flattening

[Old Murgh]

Greetings, and I hope I'm not repeating a Q answered elsewhere, but I have searched for quite a while, and nowhere found the answer to what I am wondering about.

I have a simple model where three pentagonal faces lean in to join each other, sharing the same upper vertex, and their upper two edges.connect.

In arriving at this shape, this upper vertex is at a set coordinate (Y=10), and all three pentagons bottom two vertices (Y=0). Having arrived at this by hand, my pentagons aren't perfectly flat however, and so I flatten the faces that make up each pentagon, and it looks fine to the eye.

That does disturb my measurements however, I lose my clean coordinates of top vertex Y=10 and bottom vertices of Y=0. They shift to a nearby point with many decimals. Can't I preserve my desired perfect coordinates?

I used W3D a bit many years ago, and I am relearning, so my skills are patchy and lacking at places, but I have an idea that I ought to be able to lock a vertex to a set of coords or at least an axis, so that other vertices give way when I do an operation like flattening. Or some other way to partially control what is rigid and flexible.

I realise there are situations where this operation would be impossible, but in this case, seen from Y perspective, these three pentagons form an irregular hexagon, there are supporting minor faces that I hope will take the flexible burden. I am fine with all other vertices to shift wherever they need, but in this odd circus tent I just want my ground to be at 0 and the top of the tent pole to be 10.. Is this possible? Or if it's not I need to know so I will stop trying.

I hope I've explained this sufficiently clear, and if not I can of course return with better images and improve my description.

[micheus]

It's hard to imagine the geometry of your model, but I tried to guess how it looks like.

...and I also think you will not have a solution, but I'm going to show how you can flatten faces and preserve those vertex in the top-corner in their location.
This way I think you can try by yourself using your model and see if you find a solution.



In the final result I replicated the steps for the right pentagon - which will deform the left one. Then I repeat the process once for the left and right.

[Old Murgh]

Thank you for taking the time to thoroughly demonstrate. I take it there is no easy "anchoring vertex" or "axis lock" fix then.

But I think i see what you did, by alternating the connecting lines within the face before the flattening process, I could maybe force the result I want. I will continue to try.

[Old Murgh]

Since you found it hard to imagine my geometry, I thought I'd give it another try with more visual effort.
This is the simple model and its reference card. A geometrical impossibility? Possibly.


By the eye, I can get fairly close, while retaining nice and perfect vertex coordinates. Simplicity is the guiding star here.

But obviously one can only get so close and the pentagons will not be perfectly flat. Enter the need for the "anchor vertex" command when performing the flatten.

These are the desired goals. Seeing this does it change the way you understood my initial question?

I have tried my best to tug and pull as you described below, but being a three-pronged problem I get so far outside my goals that I keep starting over again.

Seeing this now, is there maybe an altogether different way you would have tackled arriving at this simple design? Since I started this shape with a slice of a perfect dodecahedron I know I had perfect pentagons initially, but somewhere despite my best efforts, I lost it.

Or am I wrong in thinking it's possible using Wings?

[micheus]

The blueprint shows the object slightly different of what I had in mind. I'm going to evaluate it tomorrow. (Time to bed here )

[Old Murgh]

Great thank you.

for completeness, these are the views from -Z and -Y

[micheus]

The reference image is incomplete, since it doesn't includes the back and top views. Also the side view is a little compromised (cut). So, for approximation from the available views I built them.

If we consider the three visible pentagon having the exact same size and following the "rules" you set, it should look like this:

* This is in orthographic view

As we can see, it seems to be impossible to reach that shape in the reference without distort the pentagons.

Then, in order to keep those "anchor" vertices in that place and make those faces flat we are going to get the pentagon in the front view horizontally shrunken (red dots):


All faces flatten (coplanar vertices)
I focused in the front faces, so the back vertices were not changed after the start layout and as result the side and top view are not symmetric as in the reference.

[Old Murgh]

I'm sorry to report defeat. I keep trying to see what you are explaining but there is no aha moment. (Also you mention that "pentagons having the exact same size" are the rules, and I thought I emphasised that they aren't supposed to be, the two symmetrical ones equal yes, but all they are all imperfect pentagons, however flat is the only rule, and those vertices I strive to keep at those perfect coordinates.)

When starting from (dodecahedral) scratch I realise I can scale uniform the pentagons and maintain their flatness, but that gets me nowhere in regards to maintaining my coords.

Your instructions seem to me to leap to a point I don't understand how you get to. The illustration seems to indicate a scale shrink by x-axis that would bend the connecting pentagons. And I can't parse the terminology, "focus in", I can't relate to any actionable command in Wings.

It seems you get to where I want to go, I just don't understand how you get there.