Brian, I'm afraid that I don't understand in what way they are not right.

Below is a composite image of MoI output using radii 2, 1 and 1 and a grab from a Wikipedia page: https://en.wikipedia.org/wiki/Nephroid

Look pretty similar to me, or am I barking up the wrong tree?

Mike.

Hi Mike,

It is not very important. Just came up when I wanted an actual half nephroid.
I was just observing that zooming way in to a cusp point shows a hairpin turn, rather than a corner point, a result of interpcurve.
Identifying the cusp points, and ending the interpcurve there, would result in a "corner."

For example, for 3 cusps in an angle of 2 PI, the ratio of a/b = 3. Numcycles = 1/3 becomes 2PI/3 inside the js code, and yields one lobe.
Numcycles could be changed from an integerValue to numericValue.
Circular array, or 3 interpcurves would yield the full curve...


A ranunculoid has 5 cusps.

- Brian

No sure that I've fully understood the point that you are making, Brian.
Nonetheless it has made me see that the .nod needs to be able to input multiples of pi with much greater accuracy.
So the birth of Epitrochoid2.nod
Mike.

Hi Mike,

Have you seen AL2000 (Speedy) post:

http://moi3d.com/forum/index.php?webtag=MOI&msg=7777.355

He investigates similar curve forms using CV manipulation via vectors transformation.
In the absence of a mathematical formula, he follows a mechanical logic to achieve a similar result,
As a consequence it offers greater parametric control.
If you have not already seen it, I thought you might find instructive, as I did:

http://moi3d.com/forum/index.php?webtag=MOI&msg=7777.366

James

Thanks, James, it's very impressive.

CV manipulation?

Looks like I'll need to widen my maths knowledge to begin to understand the strategy of this .nod.
And it'll be weeks or months before I've nutted out the function of many of the nodes used.

Mike.

Hi Mike

Sorry, by CV (control vertices), I mean "points".

James

Thanks for Trochoid.nod - not quite so intimidating.

Hi Mike,

To help with analysis of nod file, I've relabelled several of the nodes,
& simplified the steps by using "progression" & "extract"
rather than "interp" & "splitPts".

The vectors tips can be seen as points on the minor circle
that rotates as it orbits the origin along the path of the major circle.

Let me know if this needs further clarification.

James

For the trochoid or trochoid2 nod, please explain why the line and cone "vectors" cannot be erased.

If saved and reloaded they can be erased.

- Brian

Hi Brian

to remove vectors set visibility of "rotateVec" to "No".
See attached

James

Thank you very much, James, I'll study this tomorrow.
Mike.

Hi James.
The visibility works, but once the bVectors have been applied, it is impossible to delete them from the MoI screen, even after nod is exited.
Is there some code running in the background?

- Brian

Hi Brian,

>>Is there some code running in the background?<<

I can't say; this is perhaps a question for Karsten.
He is the author of the vector nodes.

James

Thank you James.

Hello Brian,

sorry it's a bug. The problem is an objectlist that points to the vectors geometry. It seems that the objectlist survives the closing of the nodeeditor. So MoI locks the objects as long as the list exists!?

Please try the new version of vector.js

Have a nice day
Karsten

p.s.: The vector nodes were not really in my focus and so I made the code very quick and dirty - sorry for that:-(

Thank you Karsten.

Using Compare plugin in Notepad++ shows that you made changes to vector.js.

After copying the new vector.js to the extension directory, the trochoid and trochoid2 scripts still cannot have their vectors deleted :-(

So there is an objectlist in the geometry database, which MoI cannot delete. (?)
Its objects can be lofted and extended, and such changes can be deleted, but not the original vectors.

- Brian

Hello Brian,

that's very strange. Here is the problem solved. I think that you've restarted MoI already. I'm a little bit confused.



I hope someone can check it next time!

-Karsten

Maybe my node program has some old parts?
Maybe an updated node mod would be helpful...
I'll do some more checking later.

Thanks you James and Brian for the simplified versions.
I think I've got my head around it now.
This how I've interpreted the nod.
1. Draw two concentric circles with the same number of points by using polygons.
2. Attach vectors to each point of the larger circle with direction towards the centre and length the radius of the smaller circle.
3. Rotate each vector around the point of the larger circle to which it is attached by an amount determined by several inputs.
4. Draw a curve connecting the heads of each rotated vector.

However, I don't understand fully how step 4 is achieved. In particular, what does the MoveByVec node do?
Something along the lines of 'start with the co-ordinates of point on the large circle that the vector has been rotated about and calculate the co-ordinates of a new point that corresponds with the head of the vector'?

Thanks,
Mike.

Hi Mike,

You seem to have a good grasp of it.

>> don't understand fully how step 4 is achieved.
In particular, what does the MoveByVec node do? <<

The vectors (direction+magnitude) need to act upon something.
So the points of the major circle are converted to point objects
for vector transformation then converted back to a point array,
that then in turn defines the path of the curve.

Does that make sense?

James