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Xpresso help
I want to do something that I think might be doable with Xpresso, but I don’t know how to configure the expression (I don’t have the “Xpresso” mind). Here’s the scenario:
I have a closed spline path, on which there are arrows going around and around. I made this using the Multiple Spline Attach (MSA) plugin. I want the arrows to scale up larger on their x axis as they go around the spline, but only when they pass a certain area of the spline (points 1-4). I can scale them with MSA using a scaling spline, but the problem with that is that it scales certain of the arrows which then keep their larger size as they circulate around. I want each arrow to scale as they pass a certain location on the spline and MSA won’t do this. I’ve tried other methods, such as using an FFD deformer, but it caused all kinds of weird artifacts, and wasn’t usable. It seems to me that it could be done with an Xpresso expression that tells the arrows to enlarge as they get to a certain place on the path, and then scale back down to normal after they pass it. The scaling shouldn’t be sudden, but the arrows should just grow and then shrink on their x axis only (width). I can provide a file, but you would need the MSA plugin. Any help on this is appreciated.
thanks, Jack
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5 Replies
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No MoGraph, huh?
AdamT
Cinema 4DXL8 Bodypaint*Remember: Tues. is national Shoe Day. Wear shoes to show your support for bimetalism and the designated hitter rule!*
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post the file. I have MSA, I could look at it.
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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
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Okay, long time since I messed with MSA, but as it turns out you can do this with MSA’s own tools — no need for Xpresso. You use a scale spline as in the file below and as explained in the MSA html docs.
https://www.3danvil.com/MSA_Scale%20Spline.c4d
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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
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