Jump to content
  • Advertisement
Sign in to follow this  
xdotdt

game physics page 28-29

This topic is 5063 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

I couldn't understand the portion of content. On page 28-29 of game physics dave wrote, there is the text following ------------------------------------------------------------ Consider a time-varing vector written in the body coordinate system, ¥î(t) = R(t)s(t) .. digested .. The body observer does not see the change w¡¿¥î because he is rotating with body coordinate system. ------------------------------------------------------------ note: w¡¿¥î = R's But I think that if R, s are written in body coordinate system, ¥î and d¥î/dt must be also in the same. If R is just for the transformation to world space, the body observer can't see the rotation exactly because he must be also being transformed. Moreover, D¥î/Dt = R ds/dt can't be in the body coordinate system. However Eberly said 'the quantity D¥î/Dt represents the time rate of change of ¥î relative to the body coordinates since ds/dt is what the body observer measures.' This means R is also in the same, the body coordinates. So w¡¿¥î = R's must be in the same. But Eberly also said 'the body observer does not see the change w¡¿¥î because he is rotating with body coordinate system.' How could it be? I can't understand. Please somebody, make me understood.

Share this post


Link to post
Share on other sites
Advertisement
Hey xdotdt,

I haven't read the book, but I think he means that when an two objects (observer and body) are rotating exactly relative to each other, neither can tell the other one is moving. For example, the earth is rotating, but you don't notice it because you are moving uniformly with it.

Hope that helped.

Keep Programming,
Hobbit

Share this post


Link to post
Share on other sites
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!