Searching for smooth movement - a travelling narrowboat

[Peter S]

I have been working on a show that is a record of a journey on the UK canals. There is a particularly tricky 340 degree turn at a place called Hawkesbury Junction.

I wanted to show a narrow boat moving down the canal and making this turn. I experimented with various approaches and ended up putting the boat as a child in a Frame. The result is as shown in the attached Backup in zip.

I thought that others, with much more experience than me, have probably tackled this problem before and wondered if anyone has a more elegant solution.

I found that the more key frames I added the more jerky the movement seemed to be. I also thought that applying the Smooth modifier to most of the key frames would result in smoother motion but that did not seem to be the case. The movement doesn't look too bad but I suspect it could be improved if only I knew how! Another thought I had was to move the turning centre for the frame and/or the boat a long way from the image but I could not get a decent result from this.

I must say I found this a very interesting learning experience even if it was rather time consuming.

Any suggestions would be much appreciated.

Peter

Moving boat_May4-2021_10-15-31.zip

[tom95521]

I think you just need to change the center of rotation outside the center of the object. If you shift and click on the circle in the center of object the mouse cursor will change and you can move it to the center of rotation outside the object.

That is a very sharp corner for a long boat.

Tom

[stranger2156]

5 hours ago, Peter S said:

Any suggestions would be much appreciated.

I'm not sure if this is what you need, just played a little. ))

Paul

Moving boat (test).pte

[tom95521]

I removed the boat from the frame and added my own keyframes so the timing is probably way off.

Tom

Moving boat_tom95521.pte

[stranger2156]

Great solution Tom, simple and effective.

[Peter S]

Thanks Tom and Paul for looking into this.

As Paul has already said your solution Tom is indeed simple and effective. The motion is nice and smooth and I see you didn't use any modifiers which is interesting. The timing seems fine. I am after all showing something that probably takes half an hour in 36 seconds!

You are right Tom it is a very tight turn for a long boat. If the wind is against you it can be a nightmare. On a bad day some assistance from a rope on the bow may be needed.

A narrowboat generally turns around its centre point but it may drift sideways. In PTE it does however clearly look better moving the centre. How did you decide where to place the centre which I notice is not consistently in one place? I am still puzzled as to how it moved in relation to the boat so I am obviously missing something.

Although many of the fundamentals remain PTE has changed enormously while I have been waiting for the Mac version. I am so pleased that it has now arrived and works so well. Unfortunately there is a lot I have forgotten in the interim and there many new things to learn.

Thanks to you both again for your help.

I also learned that the best way for me to see your changes was to download my original uploaded zip into a new folder and copy your .pte versions into that same folder.

Peter

[Peter S]

Hi Tom,

I have had another look at your key frames and I realised that the 5th one could be removed without seeming to change the result. That was the one I was most puzzled about as its centre has moved and I couldn't work out why. Did you include this one for a specific reason or was it just a part of your experimentation?

Peter

[stranger2156]

In the 5th keyframe, there is a slight correction to the direction of motion. It was made, I think, in order not to scratch the port side against the shore.

[tom95521]

Yes, the Mac version is amazing.

I think I made a slight course correction after leaving the Stop Lock. It could be removed and the rotation changed slightly at the Stop Lock. I can imagine the drift due to wind/current.

The rotation center can be changed at each keyframe but I usually try to set it one time and disable the center object property on future keyframes unless needed. I probably just made a mistake if the rotation center changes during the boat turning. You might have to fine tune the keyframes.

I think I would need a z-drive or at least a bow thruster narrowboat to make that turn.

Thanks,
Tom

 

[Peter S]

A bow thruster is certainly tempting but they can use a lot of electricity and are not problem free on canals with lots of rubbish in the water.

I decided that it all looked a bit too easy as our narrow boat was 60 ft long and the passage under the bridge is only 50 ft wide.  This meant I spent another hour rescaling the boat! Your technique still makes it look a lot easier than it sometimes is but I am very happy with the result.

Paul also seems to have spotted the reason for the course correction. It made me look more closely and have another go at making minor adjustments.

Thanks again for spending time on this and answering all my questions.

Peter

[MUR]

Hi Tom this is only an idea, that must be refined

MUR

Moving boat -1.pte

[Peter S]

Hu MUR

It's interesting to see how small changes in the position of the centre change the motion. This is one of those slides that has taken me much longer than it probably should have done but I have learned a lot along the way. As this is only represents a few minutes in a 119 day journey I think it is time settled on what I have now arrived at. This is a much better result than I would have achieved without everyone else's input and many thanks for your contribution

Peter