; body:massprops
; Define parameters for creating a sphere
(define radius 2)
;;radius
(define center (position 1 2 3))
;;center
; Make a spherical sheet body, and turn it inside-out
(define body (sheet:face (face:sphere center radius)))
;;body
(body:reverse body)
;;#[entity 2 1]
; Try to find its mass properties - by default, error thrown when encountering
a void
(define mp (body:massprops body))
;;*** Error body:massprops: body forms a void; volume not calculated
;
; Change options to obtain alternate behavior
;
; Start with the default options object
(define mpo (massprops:options))
;;mpo
; Examine the default options
mpo
;;#[massprops-options:
;; level = "volume-centroid-and-inertia",
;; accy = 0.01,
;; use-plane-info = #f,
;; plane-root = (0 0 0),
;; plane-normal = (0 0 1),
;; thickness = 0,
;; one-sided-sheet-opt = "closed-only"]
; Force calculation as a solid
(massprops-options:set-one-sided-sheet-opt mpo "solid")
;;"error"
; Calculate only volume
(massprops-options:set-level mpo "volume-only")
;;"volume-centroid-and-inertia"
; Increase the required accuracy to 0.1%
(massprops-options:set-req-rel-accy mpo 0.001)
;;0.01
; Examine the new options
mpo
;;#[massprops-options:
;; level = "volume-only",
;; accy = 0.001,
;; use-plane-info = #f,
;; plane-root = (0 0 0),
;; plane-normal = (0 0 1),
;; thickness = 0,
;; one-sided-sheet-opt = "solid"]
; Redo the calculation with the new options
(define mp (body:massprops body mpo))
;;mp
; Examine the volume
(massprops:get-volume mp)
;;-33.5103216382911
; Examine the achieved accuracy
(massprops:get-rel-accy-vol-achieved mp)
;;0
;
; Now recalculate as if the sheet was double-sided, with a small thickness
(massprops-options:set-one-sided-sheet-opt mpo "2sided")
;;"solid"
(massprops-options:set-sheet-thickness mpo 0.01)
;;0
; Calculate everything this time
(massprops-options:set-level mpo "volume-centroid-and-inertia")
;;"volume-only"
; Examine the new options one-by-one
(massprops-options:get-one-sided-sheet-opt mpo)
;;"2sided"
(massprops-options:get-sheet-thickness mpo)
;;0.01
(massprops-options:get-level mpo)
;;"volume-centroid-and-inertia"
(massprops-options:get-req-rel-accy mpo)
;;0.001
(massprops-options:get-use-plane-info mpo)
;;#f
(massprops-options:get-plane-info mpo)
;;(#[position 0 0 0] . #[gvector 0 0 1])
; Redo the calculation with the new options
(define mp (body:massprops body mpo))
;;mp
; Examine the volume
(massprops:get-volume mp)
;;0.502654824574367
; Examine the achieved accuracy
(massprops:get-rel-accy-vol-achieved mp)
;;0
; Examine the centroid
(massprops:get-centroid mp)
;;#[position 1 2 3]
; Examine the inertia
(massprops:get-inertia mp)
;;(7.87492558499842 1.00530964914873 1.5079644737231 1.00530964914873
6.3669611112
;;7531 3.0159289474462 1.5079644737231 3.0159289474462 3.85368698840348)
; Find the principal moments
(massprops:get-p-moments mp)
;;(1.34041286553164 1.34041286553165 1.34041286553164)
; Find the principal axes
(massprops:get-p-axes mp)
;;(#[gvector 1 0 0] #[gvector 0 1 0] #[gvector 0 0 1])
;
; Repeat the previous calculation with specified projection-plane information
(massprops-options:set-use-plane-info mpo #t)
;;#f
(massprops-options:set-plane-info mpo (position -1 -2 -3) (gvector 1 0 0))
;;(#[position 0 0 0] . #[gvector 0 0 1])
; Just calculate volume
(massprops-options:set-level mpo "volume-only")
;;"volume-centroid-and-inertia"
; Redo the calculation with the new options
(define mp (body:massprops body mpo))
;;mp
; Examine the volume
(massprops:get-volume mp)
;;0.502654824574367
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