user-1: I’m working on a music video with some animated liquids  reared in cinema 4D that I want to integrate over the top of some love action footage.
So far I have been exporting the liquid animations from C4D with a transparent background and simply placing over the top of my footage in after effects but the results aren’t great, since this way there are no reflections or refractions occurring between the liquid and video footage.
Does anyone know how to do this correctly to make the two elements feel genuinely integrated?
Should I be importing my video footage into c4d and exporting everything as one?
Many thanks in advance!

user3592: Capture a spherical high-dynamic range image on set from the location where the liquid will appear.  You can use either a mirror ball, 360º camera, or stitch together a panorama from multiple images.  Then, use the image in the luminance channel of a material, drop the material on a sky object, and place the sky object in your Cinema scene.  You'll probably want to make use of the "compositing" tag on your scene elements to help control what appears in your render passes (which is where you'll find the object buffer).  You can set up global illumination to cast light from the sky object if you want, but if all you're looking for is transparency, refraction, and reflection, you don't need to.
You can experiment with the HDRi textures already included with C4D, and practice compositing the rendered image before you go to all the trouble of setting up an actual light probe.  Just search for "HDR" in the content browser and pick something similar to your scene.  Often, you can get away with using these built-in ones.
You'll also want to experiment with the render settings to get something usable in your compositing app.  At minimum, you're going to need an alpha channel of some sort, you can use an object buffer to isolate where your liquid is, but you'll also need transparency, diffuse, specular, reflections, and more, depending on how you go about compositing the image.  Much of the specifics will depend on the input image, the liquid you're trying to simulate, your compositing software, and the desired end result.  Experiment, watch internet tutorials, and ask experts for specific advice whenever you get stuck.  Good luck!

-1: <p>I’m working on a music video with some animated liquids  reared in cinema 4D that I want to integrate over the top of some love action footage.</p>

<p>So far I have been exporting the liquid animations from C4D with a transparent background and simply placing over the top of my footage in after effects but the results aren’t great, since this way there are no reflections or refractions occurring between the liquid and video footage.</p>

<p>Does anyone know how to do this correctly to make the two elements feel genuinely integrated?</p>

<p>Should I be importing my video footage into c4d and exporting everything as one?</p>

<p>Many thanks in advance!</p>
 3592: <p>Capture a spherical high-dynamic range image on set from the location where the liquid will appear.  You can use either a mirror ball, 360º camera, or stitch together a panorama from multiple images.  Then, use the image in the luminance channel of a material, drop the material on a sky object, and place the sky object in your Cinema scene.  You'll probably want to make use of the "compositing" tag on your scene elements to help control what appears in your render passes (which is where you'll find the object buffer).  You can set up global illumination to cast light from the sky object if you want, but if all you're looking for is transparency, refraction, and reflection, you don't need to.</p>

<p>You can experiment with the HDRi textures already included with C4D, and practice compositing the rendered image before you go to all the trouble of setting up an actual light probe.  Just search for "HDR" in the content browser and pick something similar to your scene.  Often, you can get away with using these built-in ones.</p>

<p>You'll also want to experiment with the render settings to get something usable in your compositing app.  At minimum, you're going to need an alpha channel of some sort, you can use an object buffer to isolate where your liquid is, but you'll also need transparency, diffuse, specular, reflections, and more, depending on how you go about compositing the image.  Much of the specifics will depend on the input image, the liquid you're trying to simulate, your compositing software, and the desired end result.  Experiment, watch internet tutorials, and ask experts for specific advice whenever you get stuck.  Good luck!</p>
