Ah that is a brilliant answer! Bravo...

You have the original structure Yes!
You fill the hole Yes!
You have only planes Yes!
You have not 4 planes but 8 so better twice! :)
And you have only quads Yes!

And there is an infinity of this solution! Excellent!
Burmann's Triangles wins ! ;) Bermuda Triangle ? :)

In situ



More flat


Complete



Now the best will be a little script or Elephant for automatise the down levels
or maybe a tricky use of existing functions (Loft, Sweep, NetWork...) for have directly plane surfaces from false surfaces! (dream :)
I have seen during this little exercise than NetWork has numerous parameters! (Uniform with number of Points...)

By hands it's 20 seconds for the last 4 top quads ;)

For this : here by hands its nothing for 12 quads but when you have 200-300 it's another story :)

It's true Quads "plane" built by external perimeter!


Not like that but...

Ultima days of summer! :)

Found a little trick...

Give a constant base angle...and so possibility to put any length to the segments
so not marvelous but..all faces are now planes! :)
https://moiscript.weebly.com/uploads/3/9/3/8/3938813/last_in_translation.3dm

All blue faces are planar!
Constant angle by row...red faces are not planes! Angle not constant on the red original surface!






Taking the same length for the segment than the red structure...but as the angle is constant by rows... at the end some is missing at the right side! :)


Right side faces are a little deformed but now all yellow volume is quasi wraped!

Hi Pilou,

I am trying to make all faces on this structure coplanar as some are no trying to follow your process but how did you insert the intersecting lines from the junction points.




thanks
Alex.

You have different methods

Here is this one with the losanges...
one by one
Scale 3D the losange from center for overpass the 4 segment
Intersect (Trim) the verticals (or oriented, Normal etc..) with the 4 segments around the losange
PolyLine the 4 points



then...

With your 4 facets (FlowExtend Srf ? Very cool! )
https://moi3d.com/forum/index.php?webtag=MOI&msg=9747.21

Make boolean like this

Select 1 2 Call Boolean Isect 3 4 as "second object set"
(you can of course take more facets in a pass - in your case 7 vertical Quads selection)
that gives the 4 points for PolyLines then Planar...erase not wanted ...etc
But it's an hard work because only "manual"! ;)

For more easy use
Copy Move facets and then process else all will be a mess above the original! ;)
And be more precise than me on these speedy test! (top facet is not well aligned on the b corner! :)

You can ask "Show points" on the result of the Boolean operation!



and ask the native function by Press TAB and write ShrinkTrimmedSrf or make a shortcut
if you don' twant to see big larger of points ;) (maybe that lost some history (?) )

But not sure that is a good thing : more little mess than other! :)

Hi Pilou,
Thanks for link for FLOW EXTEND SCRIPT another great script - I am trying to add the outer boundary 4 points as in your model whats the best process to add those are they just drawn upwards towards Z or are they aligned to the planes in that section.

Thanks again.

These segments can be many things!
Normal to the center of losange then move in their 4 places for intersection with the future growing plane from the losange
Vertical Z...
Inclined to a groundbase for be aligned at something...
etc...
all this will give slightly different results for your Plane following that you want ...

thanks again Pilou a manual process but logical will let you know how the project transpires hoping to make each panel a bolted together plate of steel.

Hi Pilou,

Having trouble with this section of workflow - trying to get the intersection of the lines and the planar surface.


Make boolean like this

Select 1 2 Call Boolean Isect 3 4 as "second object set"
(you can of course take more facets in a pass - in your case 7 vertical Quads selection)
that gives the 4 points for PolyLines then Planar...erase not wanted ...etc
But it's an hard work because only "manual"! ;)

The Boolean ISect are more for see and Keep Surfaces (or Volumes) Intersection!

So
By Default
Just select all lines
Call Trim
Click Plane
Points are shown for info to remove or not but hidden as soon as you valid the Trim!

Re-select the Lines and ask Show Points if you want to see them again for any reasons!
...

so with your file

thanks for you input Pilou much appreciated will send progress updates as it materialises.