【转帖】oddbellipse rotation value
 

oddbellipse rotation value ?
oddbellipse rotation value ?
hi,
i'm having some problems with ellipse element : i succeded in getting everything i needed to draw the ellipse or elliptical arc in a java applet but i cannot find out how to obtain rotation angle so as to draw it properly... is anybody have an idea please ? i was thinking about computing it with values like center, angleatparam function, ... but there might be an easier way to get it, isn't it ?
ps : if someone is able to explain me what is the double value we have to pass in to function oddbellipse::angleatparam(double value) ?
thanks a million.
..:. daymo .:..

if i understood correctly, try
odgevector3d::kxaxis.angleto(pell->majoraxis(), odgevector3d::kzaxis);
sincerely yours,
george udov
oddbellipse::angleatparam() ..
hi,
from arx-help:
double angleatparam(double param) const;
param input parameter to evaluate
this function returns the first period equivalent of the angle at the param location on the ellipse. the returned angle will be in the range -pi to pi.
the ellipse's majoraxis vector is the zero angle. positive angles are counter-clockwise when looking down the ellipse's normal vector (that is, right-hand rule).
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from me:
the param is a distance value on the ellipse ( i think from the start
point counter-clockwise)
that gives a destination point on the ellipse and an angle for this point.
hope this helps,
achim
quote:
originally posted by george udov
if i understood correctly, try
odgevector3d::kxaxis.angleto(pell->majoraxis(), odgevector3d::kzaxis);
ok thanks george,
you definitely understood properly. it works fine.