Thanks. I did not know you could force an avi render beyond the standard framerates. That ought to do it.
Tor

And, while we're at it, I noticed yesterday there's a "keyframe every ___ frames" option when I encode for streaming (under the Video tab). I read the Help topic concerning this but I can't exactly figure out what it does exactly. Can you answer that please? What exactly happens if I put more / too much / less / too little of it? How does it affects the image?
Thanks...

I tried it.
The framerate can not be set to 60 by the drop-down menu, but it is possible to write directly in the box.

If you do this in the middle of an edit you can copy the event, paste it somewhere at the back of the project where you can render it undisturbed (loop section only)and without having to open another instance of Vegas. But do zero out all fades, FXs, Pan/Crops and stuff first. See Chienworks' post for the render details.
Then you open the rendered file in the Trimmer and right-click-drag it in place. Select Add as takes on the menu. You will then inherit all settings (all the ones you zeroed out).
Tor

Have you tried to drag the little question mark over the appropriate box? There's info to be had that way.
I believe the keyframes are reference frames containing all the details, while the others are sort of interim. Higher number of keyframes per sec makes for bigger files.
Tor

fUtZ: streaming media (and other compressed types) do not contain the full image for each frame. Most of the frames are merely descriptions of how the frame differs from the last one. Since video often consists of frames that change gradually from one to the next, this is a very efficient way to compress the data. It does have two problems though. Eventually there will be a big enough change in the image that the differences are prohibitively large. It's also impossible to instantly display one of these frames or start playing from one since the player must back up and build the frame from previous differences. To combat both these problems, occasionally a complete frame is inserted as a "keyframe". The more keyframes you have, the more accurate the playback will be, and the more places you'll have in the stream that can be used for starting the playback. The downside of keyframes is that they take up much more space than other frames do. You have the option of trading off compression for more keyframes if you wish, or having fewer keyframes for smaller files.

Probably the default value has been very carefully chosen to give good results in most cases.

An AVI file can be at any frame rate and resolution as far as I know. Its basically a wrapper with some info in the header to tell anything trying to read it about the resolution, frame rate and encoding. Of course that doesn't mean anything can play what you create!

Gentlemen,
you can achieve exactly the same result using a velocity envelope straight on the timeline. I will admit however that this approah is one hell of a lot less confusing.
When you start changing velocity you obviously loose any concept of whats happening on the timeline, rendering the section out and bringing it back in certainly makes it much less hit and miss IMHO.

Just remember VV is using frame interpolation and it does a mighty fine job but there is a limit, 300% is what VV will let you go down to. You could render that and do it again but I think your going to get very poor results.

I've seen some beautiful slomo done on an overcranked camera, don't remember the make or model but it looks wonderful.

The next big thing for digital will be variable frame rate, it will need a whole matching chain of editing and projection systems but then it will be goodbye motion artifacts.