edit [options] geometry scale FACTOR
edit [options] geometry scale X_FACTOR Y_FACTOR Z_FACTOR
edit [options] geometry scale -r FACTOR
edit [options] geometry scale -r X_FACTOR Y_FACTOR Z_FACTOR
edit [options] geometry scale [-k FROM_POS|FROM_OBJ] -a TO_POS|TO_OBJ
edit [options] geometry scale [-k SCALE_FROM] -a SCALE_TO -r FACTOR
edit [options] geometry scale [-k SCALE_FROM] -a SCALE_TO -r X_FACTOR Y_FACTOR Z_FACTOR
edit [options] geometry scale [-c CENTER_POS|CENTER_OBJ] FACTOR
edit [options] geometry scale [-c CENTER_POS|CENTER_OBJ]
X_FACTOR Y_FACTOR Z_FACTOREDIT SCALE(nged)
NAME
edit scale, edit sca - Resize one or more objects in the database by a scale factor.
On this page
SYNOPSIS
where FROM_POS, TO_POS, SCALE_FROM, SCALE_TO, and CENTER_POS each accept one to three scalar values (broadcast to a 3-vector when fewer are given), and FROM_OBJ, TO_OBJ, CENTER_OBJ are names of existing database objects whose bounding-box centers are used.
DESCRIPTION
Used to enlarge or reduce the size of one or more instances of primitive or combination objects by a scaling factor.
A scale factor greater than 1 enlarges the object; a factor between 0 and 1 shrinks it; a factor of exactly 0 or a negative factor is rejected as invalid.
Uniform scale (all three factors equal) uses the primitive’s native
scale path and is supported by all primitives. Anisotropic
(per-axis) scale (X, Y, Z factors differ) applies a diagonal scale
matrix via ft_mat and is only available for primitives that provide
that function.
The conceptual model behind edit scale uses two independent reference pairs — a SCALE ruler and a FACTOR ruler:
SCALE = vector from SCALE_FROM (-k) to SCALE_TO (-a|-r)
the reference "ruler" — measures a known distance in the scene
FACTOR = the desired result ruler — how large the result should be
expressed as the positional argument(s), or -r when combined
with a -k/-a pair
effective factor[i] = FACTOR[i] / |SCALE[i]| per axis
The three supported calling patterns are:
-
Positional (or explicit
-ralone) — supply 1 or 3 scalar factor values directly. The implicit SCALE ruler is the unit vector(1, 1, 1), so the effective factor equals FACTOR directly.scale 2andscale -r 2both double the object. -
-k FROM -a TOonly — the effective factor vector is computed asTO - FROM. When FROM is the origin this is simply TO:scale -k 0 0 0 -a 2 2 2yields factors{2, 2, 2}. -
-k FROM -a SCALE_TO -r FACTOR(two-pair form) — the-k/-apair defines the SCALE reference ruler;-ris the FACTOR ruler. The effective factor isFACTOR / |SCALE|per axis. For example:scale -k 5 10 15 -a 7 11 -2 -r 4 2 34computes SCALE=(2,1,17) and FACTOR=(4,2,34), giving effective factors (2, 2, 2) — a uniform 2× scale regardless of the absolute coordinates. This form is the primary motivation for supplying a SCALE ruler: the FROM/TO pair captures a known real-world distance and the-rvalue expresses the desired outcome in the same units.
The pivot CENTER defaults to the bounding-box center of the target
object when -c is not specified. The batch-marker . is supported
as a -c argument to use each target object’s own keypoint as the
pivot center.
The alias sca is equivalent to scale.
Global options (-S, -f, -F, -i) are described in
edit(nged).
OPTIONS
- -k SCALE_FROM_POS | SCALE_FROM_OBJ
-
Set SCALE_FROM, the tail of the SCALE reference ruler vector. Accepts 1–3 scalar values (broadcast to a 3-vector when fewer than three are given) or an object name whose bounding-box center is used. When combined with
-a SCALE_TOonly (no-r), the effective scale factor isSCALE_TO - SCALE_FROM. When combined with both-a SCALE_TOand-r FACTOR, the-k/-apair defines the SCALE reference ruler and-rprovides the FACTOR ruler; the effective factor isFACTOR / |SCALE|per axis. If absent, FROM defaults to the origin(0, 0, 0). - -a SCALE_TO_POS | SCALE_TO_OBJ
-
Set SCALE_TO as an absolute position, defining the head of the SCALE reference ruler. Required when SCALE_TO is specified as an object name. When used alone with
-k, effective factors =TO - FROM. When combined with-r FACTOR, triggers the two-pair ratio model. - -r FACTOR | X_FACTOR Y_FACTOR Z_FACTOR
-
Provide the FACTOR ruler explicitly. When used without
-k/-a, this is the direct scale factor (broadcast or per-axis). When combined with a-k/-aSCALE pair, this becomes the FACTOR ruler and the effective factor isr_vec[i] / |SCALE[i]|per axis. Accepts 1 value (broadcast to all three axes) or 3 per-axis values. - -c CENTER_POS | CENTER_OBJ |
. -
Set the pivot center from which the scale expands or contracts. Defaults to the bounding-box center of the target object. Accepts 1–3 scalar values, an object name, or the batch marker
.to use each target object’s own keypoint as the pivot center. - -n
-
Accepted for compatibility; intended to select natural origin over bounding-box center for an object argument. Has minimal effect in the current implementation.
EXAMPLES
Example 1. Double the size of cube from its center — simple forms
A single scalar factor:
mged> **edit cube scale 2**
Three equal factors (still uniform):
mged> **edit cube scale 2 2 2**
Explicit relative flag:
mged> **edit cube scale -r 2** mged> **edit cube scale -r 2 2 2**
Using the FROM/TO reference pair (origin → 2 = factor of 2):
mged> **edit cube scale -k 0 0 0 -a 2 2 2**
Example 2. Halve the size of sph.s
mged> **edit sph.s scale 0.5**
Using the FROM/TO reference pair:
mged> **edit sph.s scale -k 0 0 0 -a 0.5 0.5 0.5**
Using explicit -r:
mged> **edit sph.s scale -r 0.5**
Example 3. Scale with a fixed pivot center
Scale sph.s by 2 but keep its surface nearest the origin fixed (pivot at the origin):
mged> **edit sph.s scale -c 0 0 0 2**
Scale cube from a named object’s position as the pivot:
mged> **edit cube scale -c sphere1 2**
Scale from the cube’s own center (the default; written explicitly):
mged> **edit cube scale -c cube 2**
Example 4. Understanding the -k / -a vector model and the two-pair ratio form
When FROM is the origin and TO is the desired factor, the model is
intuitive: scale -k 0 0 0 -a F F F applies a uniform factor F.
mged> **edit cube scale -k 0 0 0 -a 3 3 3**
The above triples the object. The following halves it:
mged> **edit cube scale -k 0 0 0 -a 0.5 0.5 0.5**
When FROM is not the origin, the effective factor is simply TO - FROM.
scale -k 1 1 1 -a 3 3 3 yields factors {2, 2, 2} — it doubles,
not triples, because 3-1=2. Plan your FROM/TO values accordingly.
Two-pair (ratio) form: When -k FROM -a SCALE_TO -r FACTOR are all
supplied together, the -k/-a pair is the SCALE reference ruler and
-r is the FACTOR ruler. The effective factor is computed as
FACTOR / |SCALE| per axis. For example:
mged> **edit cube scale -k 0 0 0 -a 1 1 1 -r 2**
Here SCALE=(1,1,1) and FACTOR=(2,2,2), so effective factor = 2/1 = 2 (doubles the cube). A more complex example illustrating that the sign of SCALE components is ignored (only magnitude matters):
mged> **edit cube scale -k 5 10 15 -a 7 11 -2 -r 4 2 34**
SCALE vector = (2, 1, -17), |per axis| = (2, 1, 17). FACTOR = (4, 2, 34). effective = (4/2, 2/1, 34/17) = (2, 2, 2) — a uniform 2× scale.
This form is most useful when the SCALE ruler is derived from known
scene measurements: specify FROM and TO as points that span a known
reference distance, then use -r to state the desired result size.
Example 5. Non-uniform (anisotropic) scale: stretch X by 2, shrink Y by 0.5, leave Z unchanged
Only primitives that implement ft_mat support per-axis scale. For
primitives without ft_mat (e.g. arb8, bot, brep) this will
return an error:
mged> **edit ell.s scale 2 0.5 1**
The three values map to X, Y, Z scale factors respectively. A zero in any position is rejected:
mged> **edit ell.s scale 0 1 1** ← error, zero factor
Equal factors are treated as uniform (uses the native scale path):
mged> **edit ell.s scale 2 2 2** ← uniform, equivalent to scale 2
Example 6. Scale with an explicit center and an explicit factor
Apply a factor of 1.5 to cube, pivoting on sphere1’s keypoint:
mged> **edit cube scale -c sphere1 1.5**
Pivot on a world-space coordinate:
mged> **edit cube scale -c 10 0 0 1.5**
Example 7. Batch scale: each object scales from its own center using -c .
Use -c . to pivot each object on its own keypoint (bounding-box center)
in a single command per object:
mged> **edit sph.s scale -c . 2** mged> **edit other.s scale -c . 2**
The . causes each object’s own current keypoint to serve as the
pivot center, equivalent to naming each object explicitly:
mged> **edit sph.s scale -c sph.s 2** mged> **edit other.s scale -c other.s 2**
Example 8. Use the intermediate buffer: scale tentatively, then revert if unsatisfied
mged> **edit cube checkpoint** mged> **edit -i cube scale 2** mged> **edit cube revert**
SEE ALSO
edit(nged), edit rotate(nged), edit translate(nged), oscale(nged), pscale(nged)
AUTHOR
BRL-CAD Team
BUG REPORTS
Reports of bugs or problems should be submitted via electronic mail to devs@brlcad.org