dunga77
Guest
Hello, do you know if you can extrapolate this parameter?
Zac69
Guest
I do it on profiles. I select the profile face and create a sketch, then I project all geometries. Key desto > region property and select projected sketch. in the window opening selective calculates and gives me all the parameters. I don't know if that's what you need.
Stan9411
Guest
I don’t know how to do it on inventor, but in general you have to specify if you mean the static moment of area inertia, the one in mm^4 (to which definitely refers zac69), or the moment of inertia properly said, the dynamic one, in kg*mm^2.
dunga77
Guest
Thank you, unfortunately I need a variable parameter.
I create a set with ilogic with an intercapedine, see attached, where at the varying ø external and table length vary masses and consequently the moment of inertia.
Therefore I should share in the table the moment of inertia for the customer.
I create a set with ilogic with an intercapedine, see attached, where at the varying ø external and table length vary masses and consequently the moment of inertia.
Therefore I should share in the table the moment of inertia for the customer.
Attachments
Stan9411
Guest
intuitively, where you control the mass of your object, you should also have the opportunity to view the main inertia moments along the 3 axes.
I think with a google search you do before waiting for the gentleman's hand.
I think with a google search you do before waiting for the gentleman's hand.
Adahm
Guest
I don't know if I understand what you need, however with this code you extract from every part of a whole a lot of information, including: volume, mass, material, name part and moments of inertia and write them on a text file (in the example on the desktop).
I hope it's useful.
I hope it's useful.
Code:
public sub get_globalmoi_ofparts_in_this_assy()
'deskttop path
dim desktoppath as string
desktoppath = getdesktop 'getdesktop path for using the function
'write to text file for records
dim filepath as string
filepath = desktoppath & "\getprops.txt"
open filepath for output as #1
'assembly doc defintion
dim oassemblydoc as assemblydocument
set oassemblydoc = thisapplication.activedocument
'set component definition
dim ocompdef as assemblycomponentdefinition
set ocompdef = oassemblydoc.componentdefinition 'this is the overall assembly we're in
'create a list for use
dim newoccurrencelist as new collection
'get the total # of sub-parts in assembly
dim totsubpartoccurences as integer
totsubpartoccurences = ocompdef.occurrences.count
'add each sub part to the list of occurences
dim subpartcount as integer
for subpartcount = 1 to totsubpartoccurences
'for each sub part
if ocompdef.occurrences.item(subpartcount).definitiondocumenttype = kpartdocumentobject then
newoccurrencelist.add ocompdef.occurrences.item(subpartcount) 'add it to the list
end if
next
'helpers
dim lbstokg as double: lbstokg = 0.453592
dim okgtolbs as double: okgtolbs = 2.20462
dim inchtocm as double: inchtocm = 2.54
dim ocmtoin as double: ocmtoin = 0.393701
'declare desired properties
dim volume as double
dim mass as double
'top level parts
dim momentsxyz(5) as double 'xyz moments about the reference axis about it's cg
dim momentsxyzglobal(5) as double ' global to be calculated
dim momentsofprince(2) as double ' i1,i2,i3 about the principla axis
'cg placeholders
dim partcgx as double
dim partcgy as double
dim partcgz as double
dim omassprops as massproperties
'for loops
dim i as integer
dim j as integer
'iterate through the assembly and other occurrences i.e. parts in the list
dim occurcount as integer
'get the current part in the list and do the following
for occurcount = 1 to newoccurrencelist.count 'start with the first occurence
dim thisocc as componentoccurrence
set thisocc = newoccurrencelist.item(occurcount)
'this occurence defined as a partdoc
dim thisoccpardef as partdocument
set thisoccpardef = thisocc.definition.document
'part docs component def
dim thisocccompdef as componentdefinition
set thisocccompdef = thisoccpardef.componentdefinition
'part name
dim partname as string: partname = thisocc.name
'get these properties
volume = thisocc.massproperties.volume
mass = thisocc.massproperties.mass
partcgx = thisocc.massproperties.centerofmass.x
partcgy = thisocc.massproperties.centerofmass.y
partcgz = thisocc.massproperties.centerofmass.z
'define mass props to use with moi function
set omassprops = thisocc.massproperties
'check if mass property results are already available at a high accuracy level
'or better. if so, simply print out the results, else, set a flag to not cache
'the results in the document.
if omassprops.availableaccuracy <> k_high and _
omassprops.availableaccuracy <> k_veryhigh then
' set the accuracy to high.
omassprops.accuracy = k_high
'set cacheresultsoncompute property to false so that results are not saved with
'the document and hence the document is not 'dirtied'.
omassprops.cacheresultsoncompute = false
end if
'call the mass moi function
call omassprops.xyzmomentsofinertia(momentsxyz(0), momentsxyz(1), momentsxyz(2), momentsxyz(3), momentsxyz(4), momentsxyz(5))
'call the principal moi function
call omassprops.principalmomentsofinertia(momentsofprince(0), momentsofprince(1), momentsofprince(2))
'calculate global moi's using the
'parallel axis theorem
'i'(x',y',z') = i(xc,yc,zc) + md^2
'i'x',y',z' = moi gobal
'ixc,yc,zc = moi of local centroid
'm = mass
'd = normal distance between cg and iglobal ref point ( resultant distance in 3d d = sqr(d1^2 + d2^2) )
'ixx
momentsxyzglobal(0) = momentsxyz(0) + mass * math.sqr(partcgy ^ 2 + partcgz ^ 2) ^ 2
'iyy
momentsxyzglobal(1) = momentsxyz(1) + mass * math.sqr(partcgx ^ 2 + partcgz ^ 2) ^ 2
'izz
momentsxyzglobal(2) = momentsxyz(2) + mass * math.sqr(partcgx ^ 2 + partcgy ^ 2) ^ 2
'parallel axis theorem for global product mois
'i'(xy',yz',xz') = i(xyc,yzc,xzc) + m*ci*cj
'i'xz',yz',xz' = moi product gobal
'ixyc,yzc,xzc = moi of local centroid
'm = mass
'ci = x,y,z global cg coordinate
'cj = x,y,z global cg coordinate
'ixy - na
momentsxyzglobal(3) = -(momentsxyz(3) + mass * partcgx * partcgy) ' "-" iprop negative integral
'iyz - na
momentsxyzglobal(4) = -(momentsxyz(4) + mass * partcgy * partcgz) ' "-" iprop negative integral
'ixz - na
momentsxyzglobal(5) = -(momentsxyz(5) + mass * partcgx * partcgz) ' "-" iprop negative integral
'convert the moi's to usable units
for i = 0 to 5
momentsxyzglobal(i) = thisoccpardef.unitsofmeasure.convertunits(momentsxyzglobal(i), "kg cm^2", "lbmass in^2")
next
for j = 0 to 2
momentsofprince(j) = thisoccpardef.unitsofmeasure.convertunits(momentsofprince(j), "kg cm^2", "lbmass in^2")
next
'write to the txt file
write #1, "part: " & partname _
& "vol(in^3): " & volume / inchtocm ^ 3 & "," _
& " mass:" & mass / lbstokg _
& " ixx: " & momentsxyzglobal(0) _
& " iyy: " & momentsxyzglobal(1) _
& " izz: " & momentsxyzglobal(2) _
& " princ1: " & momentsofprince(0) _
& " princ2: " & momentsofprince(1) _
& " prince3: " & momentsofprince(2) _
& " material: " & thisocccompdef.material.name _
& vbnewline
' & " ixy: " & momentsxyzglobal(3) _
' & " iyz: " & momentsxyzglobal(4) _
' & " ixz: " & momentsxyzglobal(5) _
next 'next occurence i.e. part in assembly list
'close the text file
close #1
msgbox ("we're done getting part props")
end sub
function getdesktop() as string
dim owshshell as object
set owshshell = createobject("wscript.shell")
getdesktop = owshshell.specialfolders("desktop")
set owshshell = nothing
end functiondiegor
Guest
Hello adahm, I see this old post and your answer with the code. where and how should this code be inserted in inventor to have the information? Thank you.
windreef
Guest
I can't tell you exactly how. I never did.