sure it doesn’t have to be feeding from the keyframed value you can use whatever works. It should be possible to do what you want (as I understand it) fairly easily. You could even have a slider to enter the bpm then use that through a RangeMapper to control relative speed then add a resulting calculation to whatever the position for the camera at the start of this frame to get a new value you feed back into the camera at the end of the frame. The other values for the target and the light are already working so could stay the same.
It sounds like there will be some for you to absorb but the help is easy since it’s contextual (hopefully you already know that)
Like this – 9549_editabletrefoil2.c4d.zip
– as long as the null is selected you should see the BPM slider (because I gave the Null User Data and dragged the user data on the screen as a HUD control) – it’s values can be changed to whatever range you want
– in the xpresso the BPM slider value feeds into a Range Mapper which takes the input BPM values and scales them so the max out is now .001 (or 1% in slider terms) – that value (the Output Upper) can be changed to any value to make the camera and lights slide along at whatever rate you want to see for a given BPM value.
– that range mapped value is then added to wherever the camera is now (incoming from the left)
– add offsets for the target and the purple light
-then run everything through a Math Modulo so the value returns to 0 when it reaches 1 (1 being equal to 100% according to the Align Tags position value)
– and feed the new values into the camera etc to move them that much further along the spline