loops and rotate help

I seek the kind help of fool proof ways to make a loop of an animation and a one axis rotate.

The loop I kinda know that you take the keyframe of frame one and stick it onto the last frame but it seems to jump a bit.

And rotate on one axis as I know it is a bit of a chore to crate : make ipo linear and then cyclic but tweaking the ipo makes it behave weird. Any clues or help ? I am trying to test out blender as a VJ tool and want to get some loops to mix with music

Ok think like this… all you need is a loop that… well loops.

So say you have an object that you want to rotate around the x axis 360 degrees in 4 seconds.

go to frame one set everything in the right position.

Then in your IPO window select rotX in the column on the right.

Then when only rotx is selected hit ctrl-leftmouse… this creates a new point… it doesn’t matter where you click.

Now hit Tab with your mouse over the IPO window… Now you can edit the point that you created. Select the point… Hit “N” this shows you a little window with the position data for your selection.

Set the point to: vertex X = 1 and vertex Y = 0

This makes the rotation around the X axis at frame one 0 degrees.

Now you want to create another point… simply take that first point in edit mode and hit shift-d to copy it…

Set the second points position in the “N” window to: Vertex X = 101 and Vertex Y = 36

This makes the rotation around the X axis 360 degrees at frame 101.

Then go out of edit mode in the IPO window and set the curve extend mode to extrapolation. (the same effect as linear interpolation but since it really doesn’t matter what happens outside the loop I usually do this)

The trick is basicly that if you render from frame 1 to 100 and you want a loop that runs smooth… you have to have the position of the object as in frame 1… copied to 101… not 100 cause then the last frame in the animation will be the same as the first… which means it shows twice in the animation which isn’t smooth.

nifty! Thank you

For simplicity, I would put the 0-degree rotation at (say) frame 1, and the 360-degree point at (say) frame 101, and then set the ending-frame number to 100, thereby discarding the last frame in the finished output but allowing me to quickly verify that it does, indeed, match the first frame.

Remember that when you Play an animation that has been rendered into multiple files, Blender will play all of the appropriately-named files that it sees… it doesn’tstop at the frame-number. So you should empty the output-image directory before doing the final renders.

It helps considerably to switch to the IPO-window. Click one the appropriate Rot_ IPO, go into Edit mode, select a vertex, press NKEY, and look at the exact coords of that point. The point at frame-1 should be exactly 0 degrees; the ending point precisely at frame-101 and 360 degrees. The interpolation-mode of the curve should be Linear. In this way you can guarantee that the loop will be precisely correct. Your eyes, unfortunately, notice the slightest flaw.