FSXA Manifold pressure needle(s)

[euroastar350]

Hi guys,

So I'm at the stage of coding the 3D engine needles on my Trislander project and I'm stuck on the manifold pressure needles. Current;y, I have them animated from 0-50, but I'm pretty much sure I need more keyframes then what I have currently. This is what the MP gauge looks like on the Trislander and I'm trying to achieve a more smoother animation and not one that jumps from one keyframe to another. Any help is appreciated.

 

[n4gix]

I used 120 frames for my C310R manifold pressure needle:

  <PartInfo>
    <Name>C310_needle_manifold_left</Name>
    <AnimLength>120</AnimLength>
    <Animation>
      <Parameter>
        <Code>
             (A:ELECTRICAL MASTER BATTERY,bool)
             if{ (A:RECIP ENG MANIFOLD PRESSURE:1, inHg) 52 / 120 *  }
           els{  (A:RECIP ENG MANIFOLD PRESSURE:1, inHg) 52 / 120 *  }
        </Code>
        <Lag>100</Lag>
      </Parameter>
    </Animation>
  </PartInfo>

 

[euroastar350]

I used 120 frames for my C310R manifold pressure needle:

  <PartInfo>
    <Name>C310_needle_manifold_left</Name>
    <AnimLength>120</AnimLength>
    <Animation>
      <Parameter>
        <Code>
             (A:ELECTRICAL MASTER BATTERY,bool)
             if{ (A:RECIP ENG MANIFOLD PRESSURE:1, inHg) 52 / 120 *  }
           els{  (A:RECIP ENG MANIFOLD PRESSURE:1, inHg) 52 / 120 *  }
        </Code>
        <Lag>100</Lag>
      </Parameter>
    </Animation>
  </PartInfo>

So do I animate from 0-120, then collapse using trajectories?

 

[n4gix]

Forget trajectories. Don't make it more complicated than it needs to be.

Because my previous script example was from a different manifold gauge, I'll use another example which is closer to hand.

Let's start at the beginning and I'll explain my reasoning as we examine this. First of all, let's look at my manifold gauge:

Note that my gauge index begins at 10 inHg, so frames 0 through 10 have no movement at all. The highest index is 45 inHg, so to achieve smoother movement I've decided to double the total frames so the highest frame number will be 90.

First, we'll animate the needle.

1. Click on the "Auto Key" button, then with the slider at frame 0, click the "Set Key" icon button (looks like a key).
2. Move the slider to frame 20 and use the "Set Key" icon button to place a key there at index 10.
3. Move the slider to frame 30 and use the "Rotate" tool (set to Local) to index 15. When you release the mouse button, a key will be automatically placed.
4. Move the slider to frame 40 and repeat the above step (#3)
5. Continue moving the slider and use the "Rotate" tool to place a key at each numbered index point, then a final key at frame 90 (45 inHg).

Note that this technique is especially suitable for index markings that are non-linear.

Next, we will need to script the needle's animation. One of the most important things to understand is this simple forumula:

SIM: Converts simvar to keyframes: simvar * scale + bias = keyframes

To convert our sim variable to keyframes we will need to divide by 45 (max value) then multiply the result by 90 (max keyframe), so:

  <PartInfo>
    <Name>C310_needle_manifold_left</Name>
    <AnimLength>90</AnimLength>
    <Animation>
      <Parameter>
        <Code>(A:RECIP ENG MANIFOLD PRESSURE:1, inHg) 45 / 90 *</Code>
        <Lag>100</Lag>
      </Parameter>
    </Animation>
  </PartInfo>

There are other ways this could be done, but this is the easiest I've found. I hope it helps!

 

[euroastar350]

Ah so it all makes sense now, I would have never thought of doubling the keyframes when animating. Again, much appreciated Bill

 

[tgibson]

Wouldn't steps 2, 3 and 4 be keyframes 20, 30 and 40?

 

[n4gix]

Wouldn't steps 2, 3 and 4 be keyframes 20, 30 and 40?

Tom, since the index is truly linear, it would be possible but you'd still need to add a final key at 45 inHg.

I've just gotten into the habit of keying every major index point since it doesn't make any difference in terms of overhead, but can result in more accurate interpolation by the sim engine.

Also, I could have simply put the "bias" in the script instead of "wasting" the first 10 frames, but it would have made no real difference in the end result.

 

[n4gix]

Ah so it all makes sense now, I would have never thought of doubling the keyframes when animating. Again, much appreciated Bill

No problem! I'm happy to share knowledge. I note that your MP index runs from 10 to 50, so obviously some slight modification to my example script will be required. That should be simple enough to do.

 

[tgibson]

Sorry, I guess I'm confused about how you set this up Bill. So you set the 0 and 10" points at keyframe 0 (understood), then set 10" at keyframe 10 and 15" at keyframe 15, and so on to 40" at keyframe 40, then set the 45" point at keyframe 90? How do you handle the sudden change of MAP/keyframe ratio? Or do you set two keyframes at 45" - keyframe 45 and keyframe 90?

Thanks,

 

[euroastar350]

At 10, the keyframe would be 0 and 20. So basically if the manifold goes from 0-45, you would simply double the numbers...meaning at 45, it would be keyframe 90 when animating, then use the above script to get your readout/animation.

 

[tgibson]

That's how I would do it, but that's not what Bill described...

 

[n4gix]

That's how I would do it, but that's not what Bill described...

Actually that is sort of - kind of what I described, but apparently not clearly enough! Fortunately euroastar350 interpreted what I meant clearly enough...

Where I wrote "frame 10" it should have been "index 10, frame 20" to be more clear.

I've edited my "instructions" to make it more clear (I hope!). Thanks for bringing this to my attention Tom.

 

[tgibson]

OK Bill, thanks. I thought I was missing a technique I didn't understand. Nice to know the simple way is the logical one.