[Jack Cook]

Thanks, Adam, that worked. I had tried the scale spline yesterday, but with a different effect – it scaled the arrows in order from the beginning, and the arrows kept their scale as they went around the path, not decreasing or increasing in size at the place I wanted them to. It is working the way I want now, but I don’t know what the difference was. The important thing is it works.

thanks again,
Jack

[Jack Cook]

Adam,

No, unfortunately I don’t have MoGraph. I think I will look into getting it, though.

Brian,

Thanks, I’ve posted the file on my ftp site at:

ftp://ftp.whoi.edu/pub/graphics/jcook

The file is named ArrowScaling.c4d. What I want to do is make the arrows grow in size as they reach the right side of the path and then decrease as the go to the left. On the path (called WarmTrack1) the points 1-4 are in the area where the arrows need to grow larger. This represents warm surface water circulating in the North Atlantic, and the flow is greater on the eastern side so I want to show it by using larger arrows.

Jack

[Jack Cook]

You’re welcome. And you can attach objects to any or all points on the spline, just keep putting Point nodes and Null nodes into the expression.

Jack

[Jack Cook]

Hi Karl,

This is actually fairly easy using Xpresso. I’m not an expert with Xpresso by any means, but this is one thing I can do.

First, a little preparation: make a null object, and make it a child of the object you want to attach. You could probably do it without the null, but I find this gives more freedom in attaching the object.

Now to Xpresso. Put an Xpresso tag on either the spline or the object (it doesn’t really matter where it is). Open up the Xpresso editor and drag in the spline object, and the null that you made a child of your object.

In the Spline node in Xpresso, on the right side (the blue side) click the blue block and choose Object. This will put in an Object port on the right side of that node.

In the Null node, click the blue box and choose Coordinates>Global Position>Global Position. A Global position port will appear.

Now right click in the editor and choose New Node>Xpresso>General>Point. This makes a Point node. On the left of the Point node, click the red box at the top and choose Point position. Go to the Object manager, and with the Point node selected set the point index to the number of the point on the spline you want to attach the object to (you can get this from the Structure Manager).

Now connect the Spline Object port to the Point Object port, and the Null Global Position port to the Point position port, and your done. When you move the object that point on the spline will move with it.

Good luck.
Jack

[Jack Cook]

Brian, I’ve given this a go using my mooring cable and attached objects, and it works. Thank you for your help on this. I read through the Dynamics docs and went through a tutorial I found online, and then I took a look at your file and applied it to mine.

First I copied my object into a new file and then put Dynamics to it, with the idea in mind of getting it to work, and then copying it back into my animation file. But I found that although I could copy it into my file, dynamics and all, it ended up in a different position and orientation to where I want it to be. When I tried to move it, and rotate it to position it where I want it to be, everything went haywire. Is there a way to take the whole thing with Dynamics applied and reposition it, or do I have to build it in place? I put everything into a null object, and tried rotating that, but it didn’t help at all.

Jack

[Jack Cook]

Mike,

I’ll play with this a bit and see if I can understand how it works (Xpresso is like Greek to me, except for a few simple things that I’ve learned to do with it). Thanks.

Brian,

This looks very much like what I want to do, with the addition of having the whole thing move downward as it curves down and then straightens out. I think this might work. Now I have to learn dynamics! I’ll give it a go over the weekend and see what I can do.

thanks,

Jack

[Jack Cook]

No, it has to curve. It represents a mooring cable with oceanographic instruments attached along it’s length. There are floats as well. It lies floating on the surface of the water, and then a weight at the end is dropped, pulling the whole line plus instruments down. But they go down following a sort of curve, straightening out as the whole thing is submerged.

Jack

[Jack Cook]

Thanks, Adam,

I’ve got it working now. Flat projection did it. I’ve got beams now.

thanks,
Jack

[Jack Cook]

Thanks, Adam. I’ll look into that. The file I’ve used layers in has a lot of complex objects, so that could be the case. I just made a new test file, and put in a bunch of objects that had parents and children, layered them, and they rendered fine in solo mode, so it seems the problem may be in the way the objects are configured. It is an existing file that I organized into layers, so I’ll check into it to see if I can find out what’s going on.

thanks,
Jack

[Jack Cook]

Hi Adam,

No, the render icon for the layer is turned on. In fact all the icons are turned on, but I’m in solo mode. When I render in the editor, or in the Picture Viewer, I get nothing but black. If I turn off the solo icon, then everything renders normally.

Jack