What would be the best approach to model a surface which is determined by a coplanar set of 4 lines and 2 diagonal arcs?
SAKOLEVA.3dm (52.1 KB)
You can split the arcs at the center and loft them to make 4 surfaces:
loft.3dm (70.1 KB)
Those surfaces could be merged into one but that may cause you more trouble than 4 surfaces.
Of course there can’t be G1, let alone G2, continuity. Your four perimeter curves come to a point at an angle. Take a piece of mock-up foam or clay and try for yourself. If you’d make a sketch of what you really want, this - what seems to be a classic XY-question - could be solved.
beside what @Lagom said - try to model it in foam or clay:
if you bring the same set up to a square there must be reflective / rotational symmetry - 8 times the same surface rotated / mirrored:
and to allow G1 along the mirror-plane, the surface must be perpendicular to mirror, because of the symmetry.
… or must be tangent to the green helper surfaces…
and this will conflict with the square edges at the base.
a fast workflow to get a surface:
_plane
_changeDegree 3,3
_pointsOn
→ move the inner 4 pts in z by a approximate amount
_scale1d to get the precise z-height
but the diagonal section of this surface is not nice - its horizontal towards the edges.
depending on your design you should introduce (rounded or) blended corners. - but there will always be this kind of sharp look for the edge…
SAKOLEVA_square_tp.3dm (3.6 MB)
kind regards - tom