Wrong import .sat file

[dronov-dmitry]

When i import this file: https://disk.yandex.ru/d/cayCPNwgRm7w8A by this plugin It ask me convert to STEP and after that is wrong imported Not like this https://disk.yandex.ru/i/vXHWlYq3zwgfvQ But like this https://disk.yandex.ru/i/i4OKv9Xpj_0WJw

[marcocecchiscmgroup]

The reason is because the two smaller elements, the doors, have a non trivial transform from the ACIS which is not applied in the STEP conversion.

def _convertShell(acisShell, representation, shape, parentColor, transformation):
    # FIXME how to distinguish between open or closed shell?
    faces = acisShell.getFaces()
    if (len(faces) > 0):
        color = getColor(acisShell)
        defColor = parentColor if (color is None) else color
        shell = OPEN_SHELL('',[])
        for acisFace in faces:
            faces = _convertFace(acisFace, representation, defColor, representation.context)
            shell.faces += faces

            assignColor(defColor, shell, representation.context)
        return shell

    return None

[jmplonka]

Hello,

Thank you very much for the detailed explanation.

Best regards Jens

[marcocecchiscmgroup]

Jens, I think I understand why you didn't initially provide an implementation for transformations in STEP, as it is a real mess. I have drafted an implementation that works for me based on: ITEM_DEFINED_TRANSFORMATION, REPRESENTATION_RELATIONSHIP_WITH_TRANSFORMATION, SHAPE_REPRESENTATION_RELATIONSHIP, CONTEXT_DEPENDENT_SHAPE_REPRESENTATION and the like

[jmplonka]

Hi Marco, You got the point. Please, could you share an example? -Jens

[marcocecchiscmgroup]

That requires factoring out many arguments that you built implicitly. Just check this out Acis2Step.zip

[marcocecchiscmgroup]

As usual, I am using the -dbg stubs, so I am not sure that the official FreeCAD/Parts module implement Vector.rotate(), Rotation.axis() etc. Just in case;

class Rotation(object):
[...]
    def angle(self):
        return acos(self.w) * 2.0
    def axis(self):
        sin_theta_half = sin(self.angle() / 2.0)
        return Vector(self.x * sin_theta_half, self.y * sin_theta_half, self.z * sin_theta_half)

class Vector(object):
[...]
    def rotation_matrix(self, axis, angle):
        axis.normalize()
        a = cos(angle / 2.0)
        aa = a * a
        v = axis.reversed() * sin(angle / 2.0)
        b = v.x
        c = v.y
        d = v.z
        aa, bb, cc, dd = a * a, b * b, c * c, d * d
        bc, ad, ac, ab, bd, cd = b * c, a * d, a * c, a * b, b * d, c * d
        m11 = aa + bb - cc - dd
        m12 = 2 * (bc + ad)
        m13 = 2 * (bd - ac)
        m21 = 2 * (bc - ad)
        m22 = aa + cc - bb - dd
        m23 = 2 * (cd + ab)
        m31 = 2 * (bd + ac)
        m32 = 2 * (cd - ab)
        m33 = aa + dd - bb - cc
        return Matrix(m11, m12, m13, 0.0, m21, m22, m23, 0.0, m31, m32, m33, 0.0, 0.0, 0.0, 0.0, 0.0)
    def rotate(self, v, angle):
        return self.rotation_matrix(v, angle) * self
    def projectToLine(self, base, line):
        self = base * line / line.square_modulus() * line - base;
        return self