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d13 last won the day on July 5 2015

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About d13

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  1. Hi Everyone!! I'm trying to build a simple interactive rollercoaster to demonstrate some physics concepts. I came across this demo, which looks like a good start: https://www.babylonjs-playground.com/#92EYG#21 To turn this into a rollercoaster, a force would need to be applied to the box as it's climbing the first hill, and then gravity/potential energy would have take over. Does anyone know what steps I should take to start implementing this? Thanks! d13.
  2. ... or you're required to meet the W3C Web Content Accessibility Guidelines (https://www.w3.org/WAI/intro/wcag)
  3. This is a fascinating problem!!! Does no one here have any ideas on how to solve it?
  4. @aWeirdo Awesome, that works!! I hadn't considered updating the direction... and normalizing it! I also got it working by using `halleysComet.lookAt(sun)` in the update function (`halleysComet` is the emitter), and by initializing the `cometTail` particle system with this direction: cometTail.direction1 = new BABYLON.Vector3(3, 2, 16); cometTail.direction2 = new BABYLON.Vector3(-3, -2, 16); Now it always points away from the sun. Thanks so much everyone!!!!
  5. `lookAt` not a function .... oh... but it does work if I use lookAt on the emitter!
  6. This effect works pretty well, I just have to find out how to orient the tail away from the sun: cometTail.direction1 = new BABYLON.Vector3(-4, -8, 3); cometTail.direction2 = new BABYLON.Vector3(4, -8, -3);
  7. Here's a playground with a simplified version of the problem: http://www.babylonjs-playground.com/#1UGDQC#20 (I can reproduce the bunching-up effect if I use `ps.direction1 = -vectorSunToMoon`)
  8. Thanks @Amarth2Estel! Obtaining the vector between the sun and valley's comet works! But I'm not sure how to apply that vector to the comet tail emitter let vectorSunToHalley = halleysComet.position.subtract(sun.position); cometTail.direction1 = vectorSunToHalley Does that seem like it should work? In my program it has the result of bunching the particles up into a cube:
  9. Hi Everyone! I'm working on a solar system model and am currently trying to create an accurate-ish simulation of Halley's Comet. The comet tail aways points away from then sun. So, I have a two part question for any experienced users out there: 1. How can I obtain the vector between 2 meshes (in this case Halley's Comet and the Sun)? 2. Which properties do I need to set in the ParticleSystem object to make the particles emit in the direction of that vector?
  10. @Wingnut Thank you Mr, Wingnut sir, `isVisible` worked perfectly!!!
  11. Does anyone know if it's possible to set the visibility of lines created with `MeshBuilder.CreateLines`? (The reason I ask is I need to toggle lines on and off.)
  12. Yes That's correct! Pluto's weirdness is one of the reasons it was demoted as a planet.
  13. I'm scaling down by a factor of 100,000,000, but use a slider to scale up to 1:1. No, I haven't Celest System
  14. Arrgh, those calculations turned out not to be accurate enough It looks like I'm back to the drawing board again. I'll need to do one of these two things: 1. Calculate the ellipse dynamically by extrapolating from a few points of captured planet position data. 2. Figure out how to calculate an accurate ellipse using this data: orbit : { base : {a : 17.83414429 * ns.AU , e : 0.967142908, i: 162.262691, M : 360 * (438393600 / (75.1 * ns.YEAR * ns.DAY)), w : 111.332485, o : 58.420081}, day : {a : 0 , e : 0, i: 0, M : (360 / (75.1 * 365.25) ), w : 0, o : 0} } ... Can anyone make sense out of that?
  15. @Pryme8 Yes, I've been using it to move the planets and it works great - I just have no idea how to use that data to display pre-renderd orbit lines.