Hi, V5
Is there a sinewave tool. or command ?
Cheers
Steve
One way would be in Grasshopper, using an equation to create points and then interpolate
Hi,
not a GH user though
Steve
Calculate the point coordinates in Excel, export a csv file and import points
Hi,
er um what ?
Tried start end tan curve tool but got this. near but not right.
sinewave.3dm (59.6 KB)
Steve
If I draw a line from top left point to bott middle then up to top right point, then turn on control points, how do I drag out a handle, as I could then drag them out halfway and get the sine curve.
then I try the handle curve, and get the attached result. in blue.
sinewave using handle curve.3dm (65.7 KB)
Steve
Draw a curve for the centreline of your sine wave. Draw a helix using the AroundCurve option on the first curve. Play with the radius and pitch settings to get the shape right (history may help here). Use SetPT to flatten the helix to the centreline (ie, if drawing in TOP, set Z to the height of the centreline). Delete the centreline.
If you need to edit the sine wave to fit the shapes in the photo better then you will perhaps want to rebuild it with less control points first.
HTH
Jeremy
offset the center line with option both, use divide to produce the amount of points needed, trim the start point to move the start position from the offsets, finally use Crvthroughpoints.
No joke. Here’s some trigonometry for you:
Points File (.asc, .csv, .xyz, .cgo_ascii,.cgo_asci, .pts) import
You could export columns C and D as *.csv and import in Rhino. You might have to add z values in a third column… See file below
Or you draft a unit circle with R = 1 and circumference 2 x pi
Polar array a line, the end point of the circle or divide the circle 12 times and there you have the y coordinates. The x coordinates are from 0 to 2 x pi, divide this line also 12 times.
I used the _InterpCrv command to draft a curve through the 12 points.
sin_xyz.csv (229 Bytes)
sin.3dm (85.4 KB)
this is a clever and simple solution
Hi, I have followed the Divide then CurveThroughPt method.
as follows.
create two arcs with required space between.
divide 30 to get required number of ‘waves’.
Group each set of points separately.
rotate inner set to place points at mid position of outer set.
run CurveThroughPt.
attached result.
How do I get a less pointed curve ?
SINE CURVE curveThroughPt method.3dm (73.1 KB)
When I used curve with handle tool, I pulled the handles along the arc to create a custom curve shape, then rotate copied it.
This curve has no ‘see-saw’ (UK kiddy play thing sit on) handles as such.
Cheers
Steve
Don’t ask for a sine wave!
Sure you’re after a sine wave shape? The photo is very low-res to tell, but even historic British machines and watches had fairly properly designed toothed gears (top land - face - flank - bottom land) to reduce vibrations, slack and wear.
Never seen gear teeth, particularly inward facing ones, with a pure sine-wave form. That would be a lousy way to transmit the force (pressure angle/profile angle). But in any case, why not just model a single gear tooth, whatever its shape, and then copy/rotate to complete the gear?
Hi,
Its the exposed edge of a brake lining on a bomb trolley, so was a sinewave then has seen use and got a bit squished.
Steve
aha like that,
Cheers
Steve
For reference here is how Adobe Illustrator allows you to create waves, they call it ‘zig zag’.
Couple of times I’ve needed to create curtains in Rhino and this would have been very useful. Creating a helix and then flattening it before extruding creates point heavy surfaces. or is there a better way?
