Storing calculations inside class with python

Scripting
1

Hello,

I want to create a class with a number of related properties which are calculated inside the class when certain property is assigned but I can not make it…

python code below is a simplified version of my class, which does not work as expected

two values displayed on the end should not be the same, but they are…

what am I doing wrong ?

thanks in advance…

import rhinoscriptsyntax as rs

class Test:

    def __init__(self,obj=None):
    
        self.Object=obj
        self.Volume=0.0
        self.m3=0.0

    def Volume(self):
        return self.Volume
    
    def Volume(self,x):
        self.Volume=x
        self.m3=x/1000000000

    def m3(self):
         return self.m3

def m3():

    obj = rs.GetObject()

    T = Test(obj)
    vol = rs.SurfaceVolume(obj)[0]
    T.Volume =vol

    print vol
    print T.m3

return

m3()

2

Hi @AleksandarSM,

Maybe something like this?

import Rhino

class VolumeHelper(object):
    def __init__(self, obj = None):
        self.m_object = obj
        self.m_volume = Rhino.RhinoMath.UnsetValue
        self.m_m3 = Rhino.RhinoMath.UnsetValue
    
    def IsValid(self):
        rc = isinstance(self.m_object, Rhino.DocObjects.RhinoObject)
        if rc:
            rc = Rhino.RhinoMath.IsValidDouble(self.m_volume)
        if rc:
            rc = Rhino.RhinoMath.IsValidDouble(self.m_m3)
        return rc
        
    @property
    def Volume(self):
        return self.m_volume
    
    @Volume.setter
    def Volume(self, val):
        self.m_volume = val    
        self.m_m3 = val / 1000000000
        
    @property
    def M3(self):
         return self.m_m3
         
def TestVolumeHelper():
    filter = Rhino.DocObjects.ObjectType.PolysrfFilter
    rc, objref = Rhino.Input.RhinoGet.GetOneObject("Select closed polysurface", False, filter)
    if not objref or rc != Rhino.Commands.Result.Success: return rc

    obj = objref.Object()
    if not obj: return
    
    brep = objref.Brep()
    if not brep: return
    if not brep.IsSolid: return
    
    volume_helper = VolumeHelper(obj)
    volume_helper.Volume = brep.GetVolume()
    if volume_helper.IsValid:
        print(volume_helper.Volume)
        print(volume_helper.M3)
    
if __name__ == "__main__":
    TestVolumeHelper()

– Dale

3

Hello Dale,

I tried your example but it does not calculate the M3 property correctly., similar to mine

This time I get M3 value -1.23432101234e+308 regardless of the selected solid, which is the default value for the property

BR
Aleksandar

4

– Dale

5

Continuing the discussion from Storing calculations inside class with python:

Thanks a lot!

I didn’t understand at first, but then then I found this article on the subject:

https://stackoverflow.com/questions/42258224/difference-between-class-foo-class-foo-and-class-fooobject

and it is all clear now. - in Rhino we have (Iron)Python 2.xx…

BR
Aleksandar

1 Like