Need help with some expresions

[Anonymous]

Hi, need some help with expresions, i am moving and rotating some objects and whant to use some expresions to make this objects always point towards the camera some help would be apreciated.
Thanks

David Campos
Vision Uno

[Tom]

david_sito_c wrote:

Hi, need some help with expresions, i am moving and rotating some objects and whant to use some expresions to make this objects always point towards the camera some help would be apreciated.
Thanks

David Campos
Vision Uno

the lookat expression might hep you.
there is a nice example setup here:
http://www.fxguide.com/fxtips-96.html

hope this helps
tom

[Anonymous]

Great tutorial, but not what i was looking for, let me explain it better, imagine a set made of extended bicubics, a woman standing in the midel of it and surrounding her lots, but lots of bubbles(the bubbles have stuf inside) and the camera is moving, looks cool, but the bubbles are rotating. what i did? simple in the top view made a circle with the bubbles and put an axis and parented them to it, so when i rotate my axis in Y everything rotates arround the woman, animate the rotation and copy it and linked it to the bubbles like this : (axis.rotation.y)*-1, works great, but i also whant to rotate my axis in X and Z, and here is where the fun begins!!, I can do it manually, but the director is changing the speed, and angle of the rotation a lot so it would be easier to automate this:) i whant that the bubbles always looks at the camera, tried with lookat, but my expresions skils is everything but great.

David Campos
Vision Uno

[Tom]

hmm, this seems a little more complicated. I really can´t imagine exactly what you mean and I am not a big expression wizard either. Especially without the project. You probably already tried to link the other axes?
Tom

[Anonymous]

Hi, i dont know how to take snapshots inside flint, but a have a image from the top view.
What is this? Simple, in the center is an axis, that axis is the parent for my other elements, and i rotate the parent in Y and linked that to the childs with this expresion : (parent.rotation.y)*-1, works well but i can only rotate it in one axis, when i try to link the rotation of the other axis, it does not work 😥
Is there a way in flint to constrain the orientation of one object to the camera, o maybe that this objest always faces to the camera?

David Campos
Vision Uno

[Anonymous]

Hi, here is a small setup that maybe will solve your problem. All you have to do is use one of the layers Axis(like Axis7 for example) from the setup to attach the “bubble” to it. Copy this Axis as many times you need and attach to as many “bubbles” you need. Then using the controls from ROTATION_CTL start controlling the overall rotation around the center (Main_X,Y,Z which are in the same position and act as your center of rotation). If you have to change the position of the center use the upper one in the tree, in this case this will be MAIN_Z.
Hope that this will help you. If you have a problem email me and I’ll try to help.

http://www.kmarkov.com/temp/rotation.zip

Kamen

[kalthans]

you can try making an expression for each child that is the negative of the parent’s y-axis rotation

the big problem with lookat is that it only works properly with axes that don’t have any parents…it cannot evaulate the entire chain of inherited transformations of one or more parent axes above it.

[Anonymous]

Just got time to try your setup kmarkov, but when i try to open it, nothing happens ❓ , I’m using Flint 8.0.3

kalthans, thats what i did, but i also whant to rotate my parent in other axis and the childs always looks at camera, I dont mind do it by hand, but when you have 40 + elements to animate and a director who does not even know what he whants for lunch, it takes a loooong time to do changes!

Thanks a lot for you help. Here in Ecuador we dont have to work tomorrow (Feriado 😀 ), so i wont be able to try more things until monday, by the way, i already finished and the director aproved everything, but i really whant to know more about this, so if you have more suggestions they are all welcome!

David Campos
Vision Uno

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