How to tie a point-cluster to its original point ?

[Frank1000]

Hi,
I've created a cluster-with-center A on a point of an arc-curve. My aim is to constrain/position the cluster-with-center B of another curve to it. So far constraining works, but when I change the radius of arc-curve A, the cluster A is not moving along with the original point on the curve.

How is this done ?

Regards,
Frank

[myara]

If you want to "lock" your point only when you use radius, you could duplicate your curve, and apply shrink wrap to "lock" that point to the dupliated curve. It won't lock the point if you decide to move it, or move the curve manually. Or, if you move the duplicated object, it will follow the closest point of that curve.

If you want to absolutely lock that point or constrain it no matter what to another object, I think you can't do that without writing a custom scripted operator.

I wrote one to lock points (from objA), by duplicating the object (to objB), hidden it and "constraining" the locked points (cluster) to objB, so any change I do in objA will be overriden by this scripted operator.


If you understand JScript, you may be able to easily modify it to use nulls instead.
btw, I used duplicate to make it easier to write, but you should only need the points coordinates and indexes.

But now that I think about it, It shouldn't be very difficult to do something similar in ICE.

[Frank1000]

Hi Myara,

I'm trying to tie the point of curve B to arc A, so when I change the radius of arc A, curve B gets modified accordingly.



Regards,
Frank

[myara]

I see, if you are not going to change curve B radio I think the easiest way would be,

1. Create a point cluster in curve A
2. Create Cluster with Center in curve B
3. Constrain (Object to Cluster) this Null (in curve B) with curve A point cluster.

[Frank1000]

have constrained it, but seems it's sticking to the center of curve A, when I constrain-clicked on the A-point-cluster

[NNois]

just create the null (center) independantly on the 1st point, then create cluster with center with this null.
For that you select your point then use the left screen menu, not the right clic context menu

[Frank1000]

the null is not following the point it is constrain/positioned to yet when changing radius. had the same effect when i first was creating to cluster-with-center, each point one.

[myara]

have constrained it, but seems it's sticking to the center of curve A, when I constrain-clicked on the A-point-cluster

That's because you are not using Object to Cluster Constraint + a cluster.

Again, a little more detailed

1. Create a point cluster in curve A, let's call this cluster A.

2. Create Cluster with Center in curve B. You can create a cluster before doing it, it doesn't matter. Let's call this Null, Null B.

3. Select Null B, go to Constraints menu, and look for the "Object to Cluster" option, it should be around the middle of the menu.

4. You should have now a Pick cursor, select cluster A now. Don't select the curve, select cluster A.

Done. Now the Null is constrained to cluster A. You can Scale, rotate, translate, increase radius, subdivision obj A and Null B will still following cluster A. Just remember that Null B won't follow any geometry changes in obj B like point translation, increasing radius, etc.

In step 4, if you haven't created the cluster in step 1, you could select just a subcomponent in step 4 but I prefer to define my cluster manually.

[Frank1000]

Thank you Myara for the detailed explanation. In fact i need the point on curve B, to follow the point on arc-curve A, when i change the radius of arc-curve A. Is this an ICE task only or is there another way to achieve this with usual SI tools too ?

Regards,
Frank

[myara]

Thank you Myara for the detailed explanation. In fact i need the point on curve B, to follow the point on arc-curve A, when i change the radius of arc-curve A. Is this an ICE task only or is there another way to achieve this with usual SI tools too ?

If you're not going to change the geometry in curve B, it should work as I explained.

[Frank1000]

ah ok, great

thx