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View Full Version : instanced arrows on a curve

edley
04-09-2009, 07:39 PM
I've seen a lot of posts on this forum regarding this and I still can't seem to get it to work. I've attached a scene file of what I'm trying to do. I have a flow path object and I've instanced the particle with a polygon arrow. So far so good. What I'm having trouble with is getting the arrows to follow the curve. The arrows follow the general shape of the curve but they are offset from the curve and they don't rotate along the curve direction. Seems like a pretty basic thing to do but I've just not had much luck. Does anyone know of a a solution. Thanks so much, edley
skunk184
04-10-2009, 09:30 AM
first thing i did was put your original arrow at the world origin and froze transforms.
instances are always better to start at 0,0,0

then i added a per particle VECTOR attribute called offset to the particleShape;

then i modified the curve flow expression a little in the particleShape

in creation amd runtime i just added these lines

to the start >
//change values to change offset X,Y,Z
offset = <<0, 0, -4>> ;

to the end >
// add this to offset the instance but not the particle
offset = $rampValues + $curveOffset + offset ;

then goto the particleShape > instancer(geometry replacement)
check allow all data types.
set position to offset
set aim direction to velocity
done

you could add attributes so you dont have to go into the expressions to change the offset values

cheers

Craig
edley
04-10-2009, 06:01 PM
Craig, thanks for the response. I'm not exactly sure how to do what you've explained so I am trying to download your example file and view it so I can follow your instructions. It won't let me download it. Not sure why. The site says I don't have privileges but I logged in successfully. Can you please upload it again or send it to edt@exponent.com. Again, I appreciate your help. Thanks, edley
edley
04-10-2009, 06:33 PM
Craig, I was able to finally get the file but I can't open it. I'm still using Maya 6.5, I still can't get my company to upgrade me. What version are you using? Thanks, edley
skunk184
04-11-2009, 07:04 AM
Hey Edley,

I am using 2009 ,so i have resaved the file as .ma and changed the header so it should open in 6.5 . It opens fine in 2008 but thats as far as i can back test it.
any questions just post and i'll try to answer .

cheers

Craig
edley
04-14-2009, 10:51 PM
Craig, thanks so much. I was able to open your file and see the changes you made. I made the same changes to my file and....it works! Very much appreciated. edley
skunk184
04-15-2009, 06:27 AM
No worries :-) glad i could help.
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