Can we design scene in 720p and export to 4k?

For illustrator assets in particular there is a little bit of a "draft mode" option that might help a bit. It is on a per puppet basis, not per scene, but it can make a significant difference in rendering performance. Switch it back to a higher option before you export.

Also, +1 on David's point that a scene level draft mode option is a good feature idea. Another customer suggested something similar recently, even.

DT

Yes, that will affect the quality. Media Encoder is going to take the size of your Character Animator comp and then scale it up to 4K. If you want to export 4K you have to animate with a matching comp size.

You could change your comp to 4K at the end before exporting, but because anchor points are invisible in CH it becomes difficult to scale from the place you want to and this is a less-than-easy task. You would have to scale and reposition all of your elements. A feature to change the scale of a comp would be a great feature request though. https://adobe-video.uservoice.com/forums/911317-character-animator