CSS3 animation function for smooth 3D revolution?

Question

I have this pen which tries to emulate an object revolving around something. This works, but it isn't smooth. While revolving it pauses around the left and right edges.

I thought it had something to do with animation-timing-function but can't get the desired result with any of the in-built functions like ease-in-out or linear or a custom cubic-bezier function.

How can I make the animation feel smooth? If there are better ways something like this can be done, feel free to let me know.

.overlay {
  background-image: -webkit-repeating-linear-gradient(0deg, transparent, transparent 1%, rgb(255, 255, 255) 2%, rgb(255, 255, 255) 2%);
  background-image: repeating-linear-gradient(90deg, transparent, transparent 1%, rgb(255, 255, 255) 2%, rgb(255, 255, 255) 2%);
  height: 200px;
  position: relative;
  width: 40%;
  margin: auto;
}
.circle {
  width: 100px;
  height: 100px;
  border-radius: 50%;
  background: #888;
  position: absolute;
  z-index: -1;
  left: 0;
  display: inline-block;
}
.move {
  -webkit-animation: moveAndGlow 2s infinite ease-in-out;
  animation: moveAndGlow 2s infinite ease-in-out;
}
@-webkit-keyframes moveAndGlow {
  25% {
    background: #ccc;
    -webkit-transform: scale(.5);
    transform: scale(.5);
    margin-top: 25px;
  }
  50% {
    left: 100%;
    margin-left: -100px;
    background: #888;
    -webkit-transform: scale(1);
    transform: scale(1);
    margin-top: 0;
  }
  75% {
    background: #000;
    -webkit-transform: scale(1.5);
    transform: scale(1.5);
    margin-top: 25px;
  }
}
@keyframes moveAndGlow {
  25% {
    background: #ccc;
    -webkit-transform: scale(.5);
    transform: scale(.5);
    margin-top: 25px;
  }
  50% {
    left: 100%;
    margin-left: -100px;
    background: #888;
    -webkit-transform: scale(1);
    transform: scale(1);
    margin-top: 0;
  }
  75% {
    background: #000;
    -webkit-transform: scale(1.5);
    transform: scale(1.5);
    margin-top: 25px;
  }
}

<div class="overlay">
  <span class="circle move"></span>
</div>

Answer 1

If you want to move you element in a 3d environement, you can use the perspective property and actual 3d rotation.

Right now you are animating on straight lines between positions so simulating a rotation is almost imposible. I built the following example, you will need to tweak the size to fit it into your project but you should get the idea.

Also note that I put the gradient background in a pseudo element so it appear in front of the moving object :

.overlay {
  height: 200px;
  position: relative;
  width: 40%;
  margin: auto;
  perspective:500px;
  margin-top:50px;
}
.overlay:after{
  content:'';
  position:absolute;
  top:-100px; left:-10%;
  width:120%; height:100%;
  background-image: repeating-linear-gradient(90deg, transparent, transparent 1%, rgb(255, 255, 255) 2%, rgb(255, 255, 255) 2%);
}

.circle {
  width: 100px;
  height: 100px;
  border-radius: 50%;
  background: #888;
  position: absolute;
  z-index: -1;
  left: 50%;
  margin-left:-50px;
  transform: rotateY(0deg) translateX(-100px) rotateY(0deg);
  display: inline-block;
}

.move {
  animation: moveAndGlow 2s infinite linear;
}

@keyframes moveAndGlow {
  to{  transform:rotateY(360deg) translateX(-100px) rotateY(-360deg); }
}

<div class="overlay">
  <span class="circle move"></span>
</div>