Category: Cockpits

Manipulators and VR Part 1: From Mouse to Mechanism

For airplane authors, the biggest question VR brings up is: what do I have to do to my aircraft to make this work? This is the first of three posts explaining not only how manipulation works with VR, but why we made our decisions and how we got here. Bear with me – this will end with specific recommendations for what to do with your aircraft.

A Long Time Ago…

Old-timers like me will remember that when the 3-d cockpit first came out, almost all of the “brains” of it were powered by clicking on the 2-d panel, which was “mapped” to the 3-d cockpit.  X-Plane would find out where your mouse click intersected the 3-d cockpit, find the texture location on that triangle, and map that back to the 2-d panel.

This seemed pretty cool when it came out 15 years ago, but as authors started making more sophisticated 3-d cockpits, it became clear that we needed a way to specify how the mouse worked directly with the 3-d cockpit shape, because the mapping back to the 2-d wouldn’t allow the user to do basic things like dragging a throttle.

Thus in X-Plane 9 we added the first set of manipulators – tags on the 3-d mesh of a cockpit specifying what happens when the user clicks on it. The manipulator could specify a dataref to modify, a command to actuate, and some data about what kind of mouse click operation was happening.

The key words here are mouse click. The original manipulators were designed entirely in terms of a mouse on a 2-d screen; they were designed to be exactly as powerful as a 2-d panel system, which was of coarse also totally mouse-centric. The relationship between the generic instruments and the original manipulators is pretty tight.

Moving to Mechanisms

The good part of the original manipulator system was that it was very flexible – mouse-centric handlers were a low level tool around which authors could do whatever they wanted.

The down-side of this design was that mouse-centric handlers were a low level tool around which authors could do whatever we want. We examined our own default fleet of a dozen or so aircraft and found that no two aircraft’s cockpits operated the same way, and almost all of them had at least some aspect that was hard to use – a poor manipulator choice for the job.

Knobs were, in particular, quite difficult – the original 2-d panel system used click-and-hold over a knob to actuate it, but authors working in 3-d had often used drag actions to do knobs, and the drag actions would respond differently depending on camera angle. We received approximately 8,452,124 bug reports that the knobs in the 747 were hard to use specifically because of this.

So during X-Plane 10, we added some new manipulators to X-Plane, and they had a very different philosophy: the manipulator described what was happening in the simulated aircraft, and X-Plane picked a mouse behavior to make that work. The new manipulators described knobs that turned and switches that either flipped left-right or up-down.  These manipulators reacted to the scroll wheel automatically because X-Plane knows what the knob is and therefore what a reasonable scroll-wheel interaction should be. (By comparison, with the old-style manipulators, the author has to specify what a reasonable scroll-wheel action is.)

Real Interaction Things Before It Was Cool

As it turns out, mechanism-centric manipulators are a lot better for VR than mouse-centric ones. Consider two cases:

  • The 2-d axis manipulator (ATTR_manip_drag_xy) specifies what happens when the mouse moves up-down and left-right, relative to the screen. What on earth does that mean in VR? Even if we made something that tracks up-down and left-right relative to the screens of the HMD, the results would be completely weird because the “thing” in the cockpit would not move the way your hand was moving. With a mouse, a mis-match between mouse and aircraft isn’t surprising, but in VR, it’s weird to reach out and touch something and have it behave the wrong way.
  • The knob manipulator. It describes a knob that does things when turned clockwise or counter-clockwise.  This is pretty easy to deal with – you click it with your controller and turn your wrist clock-wise or counter-clockwise and it turns.  Because we know what the mechanism is (and not just what the mouse should do) we can make a good decision about how to handle this manipulator in VR.

As it turns out, we ran into this problem of not doing what to do with the mouse, and needing to know what the mechanism was before we even started looking at VR. The exact same problem (“I want to touch the 3-d cockpit as if it was a thing and have it respond in the expected way”) exists in VR and on X-Plane Mobile!

Because X-Plane mobile runs on a touch screen and you have your physical finger on a switch, there are a lot of cases where the switch has to track really well and work the right way.  If the switch goes up and down, you want to flick your finger up to turn the switch on; if it goes left-right you want to flick left and right, and anything else is astonishing.

So X-Plane mobile set us on this path toward mechanism-based manipulators, and VR further drove us in that direction, since both have the same physical, non-mouse environment where a user directly interacts with the 3-d cockpit.

Guidance For Authors

So as an author, what should you do when working on a 3-d cockpit? My answer is: use some of the manipulators, but not others, to model the way things work in 3-d.

Use these manipulators ALWAYS

These manipulators are the best way to create certain physical mechanisms – use them every time this case applies to your aircraft.

ATTR_manip_drag_axis. Use this for a physical mechanism that slides along a linear path, like the throttle handle of a Cessna.

ATTR_manip_drag_rotate. Use this for a physical mechanism that rotates around a fixed point, like the throttle handles of a 737, or a trim wheel.  (Prefer this to the old technique of putting a drag axis along the edge of the throttle handles.)

ATTR_manip_noop. Use this to make a manipulator that blocks the mechanism behind it from being touched, e.g. the safety guard plate over a switch.

ATTR_manip_command. Use this for push buttons that actuate momentarily while a button is held down, like a button to motor a starter that you push in and hold down.

ATTR_manip_command_knob, ATTR_manip_command_switch_up_down, ATTR_manip_command_switch_left_right. Use these for knobs and switches with 3 or more positions that rotate or move. Pick the right manipulator for the mechanism!

ATTR_manip_axis_knob, ATTR_manip_axis_switch_up_down, ATTR_manip_axis_switch_left_right. These provide an alternative to the above manipulators when you must use a dataref. We recommend commands over datarefs any time you have a choice; the command system provides better interoperability between custom plugins, custom aircraft, and custom hardware.

ATTR_manip_command_switch_left_right2, ATTR_manip_command_switch_up_down2, ATTR_manip_command_knob2. Use these for knobs and switches with exactly two positions. You can use these to get a simple click-to-toggle with the mouse (quicker and easier for mouse users) while getting real 3-d movement in VR.

Use These Manipulators Sometimes

These manipulators are not perfect fits with physical motions and may require tweaking for VR, but they’re the best options we have now for certain problems. Try to use something from the always list instead if you can. Do not use these manipulators if the mechanism you are simulating matches something from the list above.

ATTR_manip_drag_xy. This is the only 2-axis drag we have, and is the best choice for eye-ball vents and the yoke. The yoke is special-cased in VR and should be based off of a 2-d xy manipulator. We are looking into more powerful multi-dimensional manipulation in VR, but this work won’t be complete for 10.20.

ATTR_manip_command_axis. This manipulator runs a command once based on moving a lever down or up. You should probably use a drag axis or command up-down switch, but there may be some odd mechanisms in aircraft where this manipulator is a good fit. It should not be your first-choice go-to manipulator.

ATTR_manip_push, ATTR_manip_radio, ATTR_manip_toggle. These manipulators can serve as alternatives for push-button style controls when you absolutely have to write to a dataref and not use a command.  WARNING: Do not ever use these manipulators for things that move, e.g. don’t use these for banana switches, spinning knobs, or things like that.

Do not use these manipulators

These manipulators were for mouse-centric movement and should be replaced with knob or switch manipulators.

ATTR_manip_delta, ATTR_manip_wrap. These were designed to simulate knobs by click-and-hold – use the knob manipulators instead.

ATTR_manip_drag_axis_pix. This was designed to simulate a knob by click-and-drag – use the knob manipulators instead.

We Love Commands

As you may have noticed from this list and the ever-growing size of X-Plane’s built-in command list, we love commands – they have become our go-to mechanism for our aircraft. Commands have a few advantages over data-refs:

  1. There is a clear design in the plugin system for changing a command’s behavior. So a third party aircraft can easily “take over” the existing engine start command.  This is very, very difficult to accomplish via datarefs.
  2. Commands can be mapped directly to joystick and keyboard hardware. There is no way to bind a joystick to a dataref.*
  3. Commands can be mapped to sound to capture the act of the user “doing” the thing, regardless of whether it works. For example, if you want the click of the starter switch regardless of whether the starter motor engages (maybe the battery is dead), commands make this easy to do. Often there is no dataref for ‘the user is trying but it’s not working’.

In X-Plane 11 we’ve been moving to commands to get our planes ready for VR, the new manipulators, and FMOD sound all at once.

In the next post I’ll cover some of the issues specific to VR and the 3-d cockpit.

 

 

* Developers who write plugins that provide external interfaces to X-Plane: make sure you have a way to provide access to commands and not just datarefs!  There are things you can do only with commands and not datarefs.

Posted in Cockpits, Development, Plugins, VR by | 12 Comments

Three lesser known aircraft features for 11.10

These smaller features are likely to be overshadowed by the release of the G1000 for default aircraft in 11.10, so I decided to dedicate a blog post to promote the articles I’ve written  – you can find them among all the guides for aircraft developers: http://developer.x-plane.com/docs/aircraft/

Electric and remote gyro systems

Back in April, I flew a Mooney M20J with a KCS55A HSI in it, and realised that it was impossible to model in X-Plane correctly, so I got to work. See the manual for an explanation of this popular HSI/remote gyro system.

I’ve written a usage guide on the new datarefs and commands that I added, along with some more detailed explanation of all the different gyro systems X-Plane simulates, in this guide for aircraft developers. I also talked about the systems at length in a Youtube live stream earlier this year.

Separate GPSS autopilot mode

This is a feature that many add-on aircraft already simulate to some degree, but by means of more or less reliable plugin trickery. The X-Plane 11 default 737 and 747 are no exception. With X-Plane 11.10, a separate GPS steering mode for the autopilot becomes a standard feature.
The new datarefs and commands are explained in detail here.

Screen-only popup instrument windows

Several people who build home-cockpit setups have asked about removing the bezels from the popup displays, so they can have only the screen of a GNS430/530, FMS or G1000 instrument to put on an external monitor, with a hardware bezel around it. While this can already be achieved through some clever hacking in the Miscellaneous.prf file, we now offer a more straightforward way to do this: The popup and pop-out windows now get their bezel graphics from the library system, so you can override the bezel graphics. How to override the bezel with nothing, if your bezel is made of hardware? Simply supply a 1×1 pixel blank .png as a bezel graphic, and X-Plane will know that you really want no bezel at all. In the case of a bezel-less 430, you’d put a 1×1 pixel png as the “cockpit/radios/GPS FMS/Garmin_430_2d.png” resource of your plane.

Posted in Aircraft, Aircraft & Modeling, Cockpits, Panels, Uncategorized by | 31 Comments

Request for XPlane2Blender Documentation Improvements

Please tell me what confuses you about XPlane2Blender on this bug, or here!

We are going to be releasing the XPlane2Blender 3.4 beta soon, and with it, a refresh of the UI and documentation. Thanks to a great e-mail about a lack of documentation, it was put as an important part of 3.4 release roadmap. It goes to show… we can’t fix it if we don’t know what’s wrong, even if its not a code problem. And we do want to fix it, I swear!

In addition, I want to remind everyone a core part of the Laminar Research philosophy, identity, and business plan is a thriving modding and third-party plugin ecosystem. Aside from build scripts and the like, Laminar Research employees use the same scenery development tools that are available to all. This is was a deliberate choice that elevates everyone to the same level – except when there is a gap of knowledge. This is never intentional, and never benefits anyone in the long run, especially third-party-devs. If your work is suffering because we forgot that not everyone knows what every little checkbox means, tell us! We’ll put it in the bug queue like everything else, and try to get back to you, personally, quickly.

Posted in Aircraft, Aircraft & Modeling, Cockpits, Documentation, Modeling, Panels by | 29 Comments

Double Your Framerate: Pre-Fill

That got your attention, eh?  Sorry, this is not a tip on how to tune your X-Plane system; it’s a tip for aircraft authors to make sure their 3-d cockpits are running at maximum performance.

Prefill is when X-Plane blocks out the clouds that will be behind the airplane cockpit.  The biggest cause of GPU slow-down is cloud rendering, so reducing the area that the clouds have to fill is really important.

In the 2-d cockpit, X-Plane pre-fills automatically.  But in a 3-d cockpit, the airplane author has to specify which objects should be used to pre-fill.

Aircraft Authors: go watch this video or read this page to learn how to set up pre-fill in your aircraft!  If you aircraft has a 3-d cockpit this optimization is very important!

Posted in Aircraft, Cockpits, Modeling by | 9 Comments

Composite in the Panel Texture, Not 3-d

One thought on alpha and HDR and aircraft:

If you need to create a final flat part of a panel out of multiple layers, some translucent, and you are using panel texture, it is better to composite the entire piece of panel in the panel texture than to layer polygons in your OBJ.

For example, consider the annunciator display on the dashboard that many airplanes have.  There are two ways to build this panel:

  1. Model the entire thing in the panel texture.  The background can be part of the panel background, and each annunciator is a generic instrument.
  2. Each annunciator sits on a transparent background, and the background of the annunciator panel is a separate piece of non-panel texture, on a second mesh, directly behind the first.

Choose option 1!  Tom had to convert the Baron’s annunciator panel from method 2 to method 1.  A few reasons to prefer method 1:

  • The sim does not allow for truly emissive translucent lighting in an OBJ, so the results look better if composited in the panel texture.
  • You can get shadowing artifacts between the polygon layers.
  • Spill lighting on the dashboard will not look quite right if there is alpha.

You won’t use up that more panel texture, but you’ll make your life easier. This technique wasn’t totally possible before, but now with GLOBAL_cockpit_lit you can alwys have your panel handle real lighting.

Posted in Aircraft & Modeling, Cockpits by | 10 Comments

New OBJ Commands

I have updated the OBJ8 specification with the new X-Plane 10.10 commands.  This blog post explains why we added some of these commands.

Pixel-Space Drag Manipulator

The pixel-space drag manipulator is a new axis manipulator whose drag length is measured in screen pixels instead of meters; its drag axes are always screen aligned, but it works both horizontally and vertically.

The goal of this manipulator is to make draggable knobs that:

  • Have a good response speed for both slow and fast drags via a non-linear curve and
  • Have the same drag sensitivity no matter what camera angle.

The axis manipulator has the problem that it works in 3-d; depending on how you look at the manipulation target (both position and rotation) the sensitivity of the drag can change radically.

Recommendation: use the regular drag-axis manipulator for levers and other physically moving items.  Use the pixel-space drag manipulator for drags where the underlying target does not move, like knobs.  Use button-type clicks for anything that just toggles – it’s easier on the user.

No Shadows

Three new attributes (GLOBAL_no_shadow, ATTR_no_shadow, and ATTR_shadow) allow you to exclude part or all of your object from shadow casting.  Shadows can make certain types of geometry, like grass billboards, look silly; excluding them from shadows fixes artifacts.

Note that ATTR_no_shadow is different from ATTR_shadow_blend..

  • ATTR_no_shadow: the geometry simply does not cast a shadow!  This is meant to exclude objects like vegetation.
  • ATTR_shadow_blend: the geometry does cast a shadow, but only if the alpha is greater than a certain ratio.  This is meant to make windows with tint cast shadows correctly.

Recommendation: fix shadowing bugs using ATTR_no_shadow for non-instanced objects, and GLOBAL_no_shadow for instanced objects.  Use the Plane-Maker check-box for parts on aircraft.

GLOBAL_cockpit_lit

This attribute lets you have your cake and eat it.  In X-Plane 9, ATTR_cockpit gives you alpha blending, but ATTR_cockpit_region gives you correct 3-d lighting.  You have to pick one or the other.

In X-Plane 10.10, GLOBAL_cockpit_lit gives you both.  It makes ATTR_cockpit use 3-d lighting (while maintaining translucency) and it makes ATTR_cockpit_region respect alpha translucency (while maintaining cockpit lighting).

You can add this attribute to any airplane.  This attribute should make it easier for authors to adopt correct 3-d lighting in their airplanes.

Recommendation: use GLOBAL_cockpit_lit on any airplane that uses ATTR_cockpit to change to 3-d lighting for your panel texture.  Also see here for more guidance.

Posted in Cockpits, Development, File Formats, Modeling by | 11 Comments

Three Plane-Maker Tricks You Should Know

Here are three obscure Plane-Maker/X-Plane features that can save you time if you developer complex aircraft.

Plane-Maker Will Copy Your Instruments

You may know that in Plane-Maker, you make your own copies of X-Plane’s PNG files to customize the look of the instruments.  But did you know that Plane-Maker will copy the images for you?

Select an instrument and type Control-P (which is the default for the command binding “pln/panel/copy_instrument_png”).  Plane-Maker will copy all PNGs for that instrument into your aircraft’s cockpit or cockpit_3d folder.  This can save you the time spent wading through X-Plane’s cockpit folder to find the right PNG files.

X-Plane Can Make a Panel Image for UV-Mapping

When you are making a 3-d cockpit, you use the 3-d panel as a texture.  But how do you know how to UV-map this texture in your cockpit?  Often the panel background (panel.png) is blank.

X-Plane can make a snapshot of your panel for you, in the exact size you need to UV map.  Use Control-Alt-Shift-Space (Command-Option-Shift-Space for Mac nerds) to run the “sim/operation/make_panel_previews” command in X-Plane.  It will make a PNG file in your aircraft called Panel_preview.png – it’s just like Panel.png but with the instruments drawn in – perfect for UV mapping.

Plane-Maker Will Tell You What’s Wrong

That sad face icon in top bar of the Plane-Maker panel editor enables “warning” mode.  In warning mode, every instrument that has a potential problem gets a red outline.  Select one instrument with a red outline and in the upper left corner of the panel you’ll see a description of what’s wrong.

This picture on the left is from Plane-Maker editing a 3-d panel. (That’s why it is just a “packed” set of instruments with no background; this panel is used as a texture for a 3-d cockpit – each instrument is UV-mapped into the right location.)

The air-speed indicator has been flagged as having a problem, and the text shows it.  In this case, the lit texture has an alpha channel, which causes the lit texture to draw incorrectly.  Fix the texture and the warning will go away.

I strongly recommend checking all Plane-Maker “red boxes” on your plane – most of the warnings will tell you about problems that would otherwise be very hard to detect.

Posted in Aircraft, Aircraft & Modeling, Cockpits, Panels, Tools by | 1 Comment

Let Your Eyes Adjust

This is a feature I looked at putting into X-Plane 9, but it turned out that it affects so many different parts of the sim (and has to be done all-or-nothing) that it got kicked to v10. Consider these two pictures of the default B777 (the lighting was not adjusted, only the time of day):

The night image looks pretty, but what’s wrong with the day image? The answer is: the small panel post lights in the night image are still casting a fair amount of light in the day image. And the result looks silly. But why?

The answer is: in real life your pupils would contract in the sun, letting in less light. The sun is really rather bright, so the daytime panel would still look normal, but the apparent power of those posts lights would be a lot less, because your eyes are less sensitive. In other words, the relative strength of the sun and post lights is wrong in the second image.

Computer monitors don’t have a huge dynamic range for how much brightness they can put out. So we can’t hope to display the absolute brightness of the scene correctly. Instead we need to make everything brighter at night (to simulate your night vision) and dimmer during the day, like this:


In this set of images, the night image is matched precisely to the previous one, but as the sun comes out, the apparent brightness of all lit textures has been scaled down to simulate the effect of your eye becoming less sensitive due to the flood of sunlight.

What’s good about the compensated image is that the weird artifacts from the post lights are gone; the relative strength of the post lights is really low in relative terms.

What happened to the EFIS and moving map? The answer is that they too are not as apparently bright relative to the sun as they would be at night.

There is one hitch here: plenty of real airplanes have light sensors for various avionics; the avionics will automatically turn up their brightness during the day. So it is possible (I am no expert on the 777) that in the real plane, as the sun rises, you might not have to adjust your instrument brightness; the sensor would do it for you. The pictures above illustrate what you would see if no automatic adjustment is made.

Auto-adjustment presents a challenge: currently two wrongs make a right. We don’t auto-adjust the brightness of instruments, but we don’t simulate the apparent visual brightness relative to the sun, and the result are instruments that look adequately bright at all times of day without user adjustment.

I think in the productized version of this feature, authors will have two options for anything lit:

  • Tie the lit instrument/texture to an auto-adjusting rheostat (e.g. brightness 1 + auto adjustment) or
  • Tie the lit instrument to the “raw” rheostat (e.g. brightness 1).

The tricky part will be finding the right mapping for legacy airplanes into the new system.

Posted in Cockpits, Development, Panels by | 8 Comments

Performance of Panel Texture vs. 3-d Cockpit

I sometimes get questions from authors considering how much to rely on a 2-d panel mapped to 3-d via the panel texture vs. a true 3-d panel. I can’t comment on what will look best, but I can comment on the relative performance characteristics of both techniques, and the answer might surprise you: in some cases you’ll get better performance by modeling directly in 3-d.

The 2-D Way

When you use the panel texture to make an object, X-Plane goes through a lot of steps to create the final result:

  1. Your panel has to be rendered in 2-d. We atlas your panel textures, but we don’t necessarily order them optimally – we don’t know the optimal order. Each generic instrument is at least one batch, perhaps even two. Those batches have very low vertex count, and the vertices are stored non-optimally on the CPU. There may be a fair number of texture changes between instruments.
  2. If you use ATTR_cockpit_region, we then go back and do the same thing…again! Why? Well, we need your panel’s raw color (“albedo” to graphics nerds) and the emissive light given off by anything self-lit separately, so that we can do correct 3-d lighting.
  3. Both of these are rendered to an off-screen texture that the video driver will feeel obligated to preserve at all costs, putting pressure on VRAM.
  4. Only when all that is done do we begin drawing your object, with the usual batches to change to panel texture and change back, perform animations, etc.

If this seems expensive, that’s because it is. Periodically users send me airplanes to look at their performance, and lately I’ve been seeing a lot more problems with 2-d panels (that fuel 3-d cockpits) being the performance bottleneck, not the 3-d modeling itself.

The 3-d Way

What if we want to go 3-d? Well, we’re going to “eat” a lot more of what your 3-d pit already has:

  • You’ll need a lot more animations to move all of those parts.
  • You’ll need new batches with ATTR_lit_level to dial up and down various lighting levels.

But you do get some advantages:

  • Geometry in objects is processed about as optimally as we possibly can. All of that work we’ve done on the rendering engine to make OBJs fast is available in your cockpit. So you can increase 3-d detail ‘for free’.
  • Your lit geometry can be drawn in a single pass (we don’t need to prepare two separate lit textures). So for example a needle would take three batches via the panel-texture route (a batch to rotate the needle for albedo, a second batch to draw the rotated night needle, and a third batch to draw the resulting texture in 3-d) but only one if you use the OBJ directly.
  • Since you organize your textures for OBJs, you can guarantee that all of the cockpit stuff is together, saving texture thrash.
  • You can use normal maps to add per pixel detail to your cockpit; panel textured geometry cannot be normal mapped.

A Balancing Act

Given the high cost of panel texture relative to native OBJ drawing, you’d think going native OBJ would be a no-brainer, right? Well, not quite.

A needle is an easy case: you can model a needle using a rotation animation, so your implementation in an OBJ and our generic instrument are quite similar. Same with the throttle lever generic instrument.

But what about a “glass pie indicator”? What about a moving map? What about a rotary?

There are some generic instruments that have “movement” for which there is no equivalent OBJ technique. With these generics, the generic instrument/panel code may be able to render the generic quite a bit more directly than your OBJ can simulate the same effect.

This is my suggestion on a cut-off: if you can directly model a generic instrument with an OBJ (needles, throttles, and other “simple moving things”), consider 3-d. If you would have to use a lot of extra texture space, copies of your mesh, or a lot of show-hides, use the panel texture.

Your goal should not be to eliminate the use of panel texture. But if you can cut panel texture down to a single 1024 x 1024 region from a larger area, you’ll probably see a performance win or a reduction in your airplane’s system requirements.

Performance Test First

Final thought: before you invest months in a complex cockpit design, mock up the “work-load” X-Plane must do and performance test it! For an OBJ, simply make one moving instrument and duplicate the mesh to get the number of expected animations. For the panel, drag out a bunch of instruments, make custom textures and just paint junk into them with photoshop. The goal is to make X-Plane do the same amount of work as it will in the final version. Then fly your test panel on target computers and observe performance.

Posted in Cockpits, Development, Modeling, Panels by | 2 Comments

Lighting Rheostats in X-Plane 9

There were a few threads regarding lighting rheostats in X-Plane 9. Here’s a short version of the issue and why we’re not changing X-Plane 9’s behavior.

X-Plane 9’s policy toward lighting rheostats is a little bit arbitrary. The sim will pre-position every lighting rheostat in the cockpit to 75% intensity on sim startup, and from that point on, we never touch them. We do not reset them when you load a new plane or reset your flight.

The result of this is that when you load a new airplane, it “inherits” the rheostat positions of the last airplane loaded. This can cause a problem if the newly loaded plane doesn’t have controls to adjust the lights (e.g. it has no instruments on the 2-d panel or manipulators on the 3-d panel, and there is no keyboard shortcut defined). A plane can be “stuck dark”.

It would be nice if X-Plane would pre-initialize the lighting rheostats on startup, but X-Plane deos not have enough information to do this. For example, on plane load, the instrument brightness should be set fairly high (so a glass cockpit can be read during the day) but the flood lights should be fairly low (to prevent loss of night vision). But X-Plane has no idea which rheostats control instruments and which control floods. So if we wanted to correctly initialize the cockpit, we wouldn’t have enough information.

To make it more complicated, some airplane authors have taken it upon themselves to initialize the cockpit via plugin code. If X-Plane were to start changing the rheostats at startup, it might undo some of what these plugins have done.

Given the difficulty of maintaining compatibility and the lack of a “correct” set of values, we decided not to change the behavior in 9.50 or 9.55.

If there’s any take-away point for airplane authors, I think it is this: provide controls for the lighting rheostats that you use in your airplane. Otherwise the user can’t turn the lights on if they are off for any reason. You can control the lighting rheostats with a generic instrument, manipulator, or the built-in instruments.

Ugly Glow

There is a separate issue that sometimes comes up: X-Plane panels can look bad when the flood lights are turned all the way up during the day. A panel can look very red and washed out, for example.

This problem comes from a mismatch of real-world lighting levels. In the real world, the sun is approximately four gajillion times more powerful than the little dome lights in an airplane. So when the sun is out, the dome light isn’t visible even if it’s turned all the way up. The dome light only looks bright when your eyes have adjusted to a no-sun condition.

What X-Plane should do (and may do in the future) is scale all cockpit lights relative to the overall daytime brightness, which would effectively dim the effect of flood lights during the day. Simply turning down flood lights when a flight is started during the day is not a full solution, as the user can simply turn them right back up again and end up with an unrealistic scene.

Suffice it to say, I think we will address these things in a v10 time frame, not a v9 time frame; in the short term it’s better to have airplanes continue to function as the author intended.

Posted in Aircraft, Cockpits, Development by | 3 Comments