Jump to content
  • Advertisement
Sign in to follow this  
giugio

Extrusion , 2d profile and 2d matrix reduction?

This topic is 2443 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

If you intended to correct an error in the post then please contact us.

Recommended Posts

hello.
I have this problem:
I have a 2d profile, an extrusion direction a depth and a 3d transformation.
The 2d profile is extruded along the extrusion direction ,for a depth .
The 3d transformation rotates the 2d profile in the profile plane.
I would like to extract the angle of rotation of the 2d profile in the profile plane after the apply of the rotation matrix.
I trying this method:
1)save a point of the profile
2)apply the trasformation matrix on the point
3)get the transformed point
4)use a dot product for get with the acos function the angle after the transformation.
like:

C3DVectorIfc pPoint = *(pProfile)[0];
double d = DEG_RAD(90.0);
pmxRes->m_X = C3DVectorIfc(1.0, 0.0, 0.0);
pmxRes->m_Y = C3DVectorIfc(0.0, cos(d), -sin(d));
pmxRes->m_Z = C3DVectorIfc(0.0, sin(d), cos(d));

C3DMatrixIfc pm = *pmxRes;
C3DVectorIfc pPointNew = (pm * pPoint);

pPointNew.Normalize();
pPoint.Normalize();
double dot=pPoint * pPointNew;
double dAngle = ACos(dot);


the problem is that this don't works.
for example:
1)pPoint = -162;-63.5;0.0
2)pPointNew= -162;0.0;-63.5
after the normalization
3)pPoint = -0.92;-0.38;0
4)pPoint = -0.92;0.0;-0.38
5)dot product: 0.85
6)double dAngle = acos(dot);
dAngle = RAD_DEG(dAngle);
dAngle = 31°????? not 90°
I think that must be a problem of the 2d coord system.
may be that I must do a projection?
Because i read that the projection is an operation that involve coordinate system reduction.

i ask this to geometric tools programmers and they say:

"What you want is to keep
track of the "coordinate frame" vectors along the axis of the beam."

i think that this is the same solution that they say
http://stackoverflow...be-along-a-path

but i'm not understand.
thanks.

Share this post


Link to post
Share on other sites
Advertisement
Sign in to follow this  

  • Advertisement
×

Important Information

By using GameDev.net, you agree to our community Guidelines, Terms of Use, and Privacy Policy.

We are the game development community.

Whether you are an indie, hobbyist, AAA developer, or just trying to learn, GameDev.net is the place for you to learn, share, and connect with the games industry. Learn more About Us or sign up!

Sign me up!