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finding a vector between to point in space
I need an expression to calculate the distance between to point in space , and a unit matrix which is pointing that way, -parallel to that line
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6 Replies
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p1 = effect(“3D Point Control”)(“3D Point”);
p2 = effect(“3D Point Control 2”)(“3D Point”);
normalize(sub(p2,p1)); // unit vectorIf for some reason you need both the length and the unit vector
v = sub(p2, p1);
L = length(v);
u = L==0 ? null : div(v,L);// you can use p2-p1 instead of sub(p2,p1), etc, AE supports it.
Xavier.
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thank you Xavier, that’s helpful , what about a normal of a plane ?
and what about multiplying those two vector in a way that you have a number, V1.V2 ? I dont know the name of math operator -
normal of the plane parallel to v1 and v2 (up to sign): normalize(cross(v1, v2));
v1.v2 : dot(v1,v2);To get all methods (math or not) available to expressions, enable the expression of a property, and click the triangle near the = sign.
It opens up the menu.Xavier.
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thank you , I just saw them now , never needed them 🙂 I know cross gives you a vector which is perpendicular to those vector you crossed. but I just have a regular plane and a camera , I know where is my camera and from that point to another point on the surface of the plane , there is just a vector. but I need to have another vector for the plane , which is its normal. so I can dot them . that way I have a number which is related to distant and angel of view.
so I need to know how I can have normal for planes .
any help on that ? -
I don’t know what plane you are talking about…
If your plane is a layer, then a normal to the “plane” can be the vector [0,0,1] (in layer coordinate system). To get the coordinates of that vector in world coordinate system, use toWorld, then normalize to get a unit vector in world system (in case your layer is scaled etc):
normalize(thisComp.layer(“Plane”).toWorld([0,0,1]));
Something like this. I barely do any 3D so i’m not sure to be honnest… That’s a whole different question from the first one 😉
If your plane is not a layer, then you should give more info about that plane…
Xavier.
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hello there again
thanks for answer, a while back I used these and I made the idea I had but it didnt give me the effect I was trying to achive,
the thing I want to do is ,to make some highlights using “CC Light Sweep” and put it on top of a layer, then I want that highlight which is kinda stright line along surface react to camera movement in a proper way. I had in mind that I can tie center point of “CClight sweep” to camera movement somehow, but how ? that’s the question.thank you for respond
shahed
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