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

Ah, yes, vector transformation. That was what hadn't quite clicked.

Doing a bit of reading around I've learned a new word: tuple
Didn't have those 50 years ago in Engineering mathematics.

Thanks,

Mike.

Hi Mike,

........UPDATED........

You got me thinking whether this was the most logical way to delineate the curve.

As an alternative the rotated vector can be added to polygon pts, and input to curve node. See attached.

James

Hi James,

re Trochoid4.nod

I like it. More straightforward and easier to understand.

Tell me, is there any reason why vMagnitude (Large circle radius) can be negative, so a range of -30 to +30 instead of simply 0 to 30?

Mike.

Hi Mike,

>>Tell me, is there any reason why vMagnitude (Large circle radius) can be negative, so a range of -30 to +30 instead of simply 0 to 30?<<

Yes the range could be simply 0 to 30, but if you dial from start to finish you'll see that the extremes (-30, 30) are not identical.

It is similar to curves/polygon node setting "TYPE" "inscribed" / "circumscribed".

Have a great weekend

James

Not seeing that, James.
Is it dependent on the values of the other inputs?
Mike.

Mike,

as shown, see attached

James