Animating polygons out of a sphere

[Brian Jones]

you can’t keyframe a change in geometry usually (you are making new vertexes and edges with an extrude). You could use two objects one with the extrude and one without – Swap the objects at the right time. Or perhaps this freebie from Nitroman would do it (don’t know but it looks promising) https://nitro4d.com/product/magic-mesh-3-0/

[Sam Treadway]

You need to do this in reverse order.

1. First, before extruding, ‘split’ the 4×6 polygon selection to use as a snapping reference later. The shortcut is U~\
2. Go to the frame where you want the extrude animation to stop (let’s call this the ‘out position’)
3. Extrude the polygons out and set a key for the points (this is point level animation so no need to key parameters or PSR
4. Then go to the frame where you want the zoom to start at.
5. Select one point at a time on the extruded surface and using the snap tool, snap them to the original location (thas surface that you split off in step 1)
6. Key the points here.

*The Animation will be completely linear but you can either scrub the timeline between the two initial keys, set new keys and then move those keys to sort of fake some easing OR simply render the animation at a higher frame rate and use speed ramping in an editor.

[Sam Treadway]

You may also want to consider pose morphing instead of explicit point level animation.
For this particular setup you described. I’d just copy the sphere, then on the first one make an extrusion with an offset of zero and then select the duplicate sphere and with the same polygon group selected make an extrusion with the offset set to whatever you like. Hide that second sphere. Then add a pose morph tag to the first sphere, set the mode to points and drag the second sphere to the bottom of the list. Then you can keyframe the slider from 0 to 100% and back and fine tune in the curve editor.

[Jim Scott]

Hi Sam,

I had a similar thought to use pose morph, but when I followed your description only the center polygon of the selected polygons moves when the strength slider is animated. It seems that Brian is correct that extrude cannot be animated. Did you actually create a working example as per your instructions? If so, could you please upload your project file so that I could see it?

Thanks

[Rick Morton]

Thanks to all. However… seems a bit over my head.
Jim… yes, I have the project but not sure how I would upload to you.
I’ve switched gears and trying a different way to show the same concept.

[Jim Scott]

Rick,
Thanks, but I was responding to Sam’s comments.

For future reference the easiest way to upload anything – screenshot, project file, etc. – is just to drag it into the message window.

[Sam Treadway]

For the Pose morph to work you’d have to use the extrude for all variations including the original ‘pose’. The main pose would simply have an extrude with the main having an extrude offset of zero. This would create polygons with a width of zero around the perimeter of the selection and cause a break in the phong shading, however. A quick workaround to that is to keep a clean version and swap out visibility when the extrusion animation begins. See the attachment for a quick example.

13375_posemorphextrusionexample.c4d.zip

[Jim Scott]

Thanks Sam. I appreciate you taking the time to make the example.