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FSDS - Animating Parts with a Tipped Axis

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Previously I covered how to animate ailerons on the Cessna 172. I thought I should cover how to do something a little more complicated and show how to do animation on a part whose axis is not perfectly straight across or up and down. With that in mind, I looked through each project in the Samples folder of FSDS looking for a part that had a rudder that was not already animated for FSX and whose axis was not straight up and down. The only one I found was the Shorts 360, so I’ll use that one in this example of how to animate a rudder that has a tipped axis.

The Shorts 360 is not one of my favorite planes by any means, but it is unique and hard to mistake. Granted, this model is not very complex and leaves a lot to be desired -no offense Paul! (Paul Lee here at Abacus designed it). In his defense though, it was designed for FSDS v1 and has been included in all FSDS versions along the way. It’s original design included textures from Fed Ex, which has since been changed to the Sucaba Cargo transport Service.

For those of you that are curious, “Sucaba” has been used by Abacus a few times over the years in some of our packages and download airlines. The name Sucaba comes from Abacus - by spelling it backward!

Moving on, I’ll start by opening the Shorts360_FedEx.fsc file found in the Samples\Shorts360_FSX folder under FSDS. Once opened, center the view on the rudder area and cycle through the parts until the rudder part is current. In this case, the rudder is called simply “Rudder”.

I notice that the axis of the Rudder part is not even close to where it needs to be. The first thing I’ll do is move the axis of the part. Like the animating an aileron example in an earlier post, I’ll need to move the axis to point where the part will rotate.

To move the axis, I’ll turn on Move mode, then I’ll hold the SHIFT key down, then click and drag the axis of the Rudder part until it sits on the rotation axis. This will be where the Rudder meets the vertical stabilizer.

Next I’ll need to rotate the axis of the part so it matches the angle shown between the Rudder and the vertical stabilizer. The axis is rotated the same way you move the part. Instead of choosing Move mode, I choose Rotate mode and again hold the SHIFT key down while I click and drag the axis until the angle of the axis matches the angle of the part.

Here I’ve zoomed in as far as I could go using the ‘i’ key on the keyboard. I need to make the angle of the axis match the slope of the part as close as possible. Also, the position of the axis needs to be as close to the edge of the part as possible. In my example, I had to again use the Move mode to adjust the position once I was zoomed in and adjusted the rotation a few times until I was sure it was correct.

Now that I have the axis of the part set, I will make a copy of the part using Edit | Copy and Edit | Paste. The new part will be called Rudder.1.

Once the copy is made, I’ll open the Part Properties on the Rudder.1 part and do 2 things:

  1. Set the Part name to rudder_percent_key
  2. Set the Parent Part to Rudder.

After clicking OK, I notice something strange:

The rudder_percent_key part has rotated! This is normal. Since the axis of the rudder_percent_key part is rotated and it was assigned to have a parent part who’s axis is also tipped, it takes on a double-tip so to speak. Obviously this is not what we want so we’ll need to fix it.

To correct this, use the Part | Reset Part Rotation menu.

This will return the axis to it’s original location.

Perfect! Now all I have to do is animate it right? Not quite… I also have to off-set the part.

There are some <Felix> that say you don’t have to do this, but I have always run into trouble trying that… Logically, if you leave it as-is and set the Keyframe 50 to the center position, then keyframe 0 to the rotated-left position and keyframe 100 to the rotated-right position, it should work - but again, I’ve always run into trouble or confusion for some reason when I do it. Offsetting the part just works, so I stick with it.

To rotate the part, I’ll use the Transform | Rotate menu. Since we want to rotate the part around the Y axis, I’ll enter negative 30 (-30) for the Y value and set the Options to Entire Part.

This will rotate the rudder part 30 degrees to the left.

Now I have to reset the axis of part so it sits back normal with the parent part. To do this I’ll select Part | Reset Axis Rotation from the menu. This will reset the axis of the part back to it’s original position.

Note: I have not tried this, but I believe that when you rotate the part to be offset, you can choose to rotate only the Vertices instead of the Entire Part. In theory, that would keep the axis where it is and rotate only the points of the part to the offset location. The end result should be the same - but again, I’m sticking with what I know and what I know works! If it ain’t broke, don’t fix it… right?

Now I have the axis of the rudder set properly, the part is offset for animation and it has a parent part with the same axis. Now we’re ready to animate… Except I forgot one small detail… I need to set the Parent part to be a Hierarchy Node or it will show up in Flight Sim. So I will quickly switch to the Rudder part and open the Part Properties and click the Hierarchy Node (no geometry) check box and click OK.

Ok - Now I’m ready to animate the rudder. I’ll again switch back to the rudder_percent_key part and enter Animation Mode. Once in Animation Mode, I can immediately set the Keyframe 0 since the part is already in the first position. I’ll check the Status Bar at the bottom of the FSDS window to be sure it reads Frame 0 | rudder_percent_key. Since it does, I’ll select Animate | Set Keyframe from the menu.

I’ll again check the Status bar to be sure it shows that the Frame 0 has been set. This is noted by the * symbol next to Frame 0:

Next I’ll move to Frame 50 by holding the N key down until the bar reads Frame 50. Once at frame 50, I’ll select the Transform | Rotate menu. Here I’ll set the Y value to 30 (not negative 30 like last time but a positive 30). I’ll confirm the Options are set to Entire Part and click OK.

After this rotation, the part will be back to its center position. I’ll check that the status bar reads Frame 50 and I’ll choose the Animate | Set Keyframe from the menu. Once done, I’ll again confirm that Frame 50 was set.

The last step is to set Frame 100 by holding down the N key until you get to Frame 100 on the Status Bar. Once on Frame 100, I’ll use the Transform | Rotate menu again and set 30 for the Y value and the Options to Entire Part. After Clicking OK, the part will not be rotated 30 degrees to the right. I’ll choose Animate | Set Keyframe to lock it in.

Now that we have our frame 0, 50 and 100 set, it’s time to compile it and take a look at it in FSX (after saving of course). I’ll click the ANI button on the toolbar to exit Animation Mode. To create the aircraft, I’ll chose the File | Create FS Object File menu and choose Aircraft File (*.MDL). Since this is a twin-engine plane and has a tricycle landing gear, I’ll choose the Cessna 208 as a reference. I know - it’s a float plane or Amphibian but we’re just testing the rudder so you’ll have to deal with a Shorts that can land on water for a bit…

I’ll be sure to click the New Aircraft box and the Copy Textures box and click OK.

For the New Aircraft Specifications, you’ll see the New Folder Name is set to FSCAD Shorts 360. For this Test, I’ll check all relevant information to Shorts just to make it easy.

Note that FSCAD was the original working title of FS Design Studio for FS2000 about 8 or 9 yeaers ago - that’s how old this basic model is!

I’ll Quickly click Yes to view the Compile Logs to see if there were any problems. Here’s what it shows:

Found dictionary file: C:\Program Files\Microsoft Games\Microsoft Flight Simulator X SDK\SDK\Environment Kit\Modeling SDK\bin\modeldef.xml
OutputFile: _temp.MDL
Output file after modification: _temp.MDL
Creating output MDL file: _temp.MDL
CRASHTREE no granularity specified
CRASHTREE completed in 00:00:00.0156250
<!– ++++ Processing Animation : rudder_percent_key ++++ –>

That means it worked. It processed the animation for the part rudder_percent_key and didn’t show an error - I’ll open up FSX and check it out! As long as I keep it in the air, I should be OK right?

So far so good - it shows up in the list and the rudder looks good from here…

Excellent…… It worked…..

Here’s a quick overview of how to animate a part with a tipped axis:

  1. Move the axis of the part to the rotation axis by using Move mode and holding the SHIFT key when clicking and dragging
  2. Rotate the axis of the part to match the axis of the needed animation by entering Rotate mode and holding the SHIFT key when clicking and dragging
  3. Make a copy of the part.
  4. Set the copy to have the correct animated part name on Part Properties.
  5. Set the part being animated to have a Parent Part - use the original part you copied in the Parent Part drop-down menu in Part Properties.
  6. Reset the Part Rotation of the animated part
  7. Rotate the part to offset the animation. A rudder is offset to the left for example. Rotate using the Transform | Rotate menu, enter Y value and choose Entire part.
  8. Reset the Axis Rotation.
  9. Enter Animation Mode and set Frame 0 to starting position.
  10. Move to frame 50
  11. Rotate part back to center (in step 7 you off set to the left using a negative number, use the same number only positive to get back to center).
  12. Set frame 50
  13. Move to frame 100
  14. Rotate the part again to right position
  15. Set frame 100
  16. Compile and check in FSX.

If you want to download this project, you can from here:

FSDS Project Shorts 360 with Animated Rudder

Posted with permission from Adam Howe and Abacus Publishing.

For more information visit Adam Howe's Flight Simulator Design Studio blog!