From the course: V-Ray 5 for 3ds Max Essential Training

IES light

From the course: V-Ray 5 for 3ds Max Essential Training

Start my 1-month free trial

IES light

- [Instructor] When creating both interior and exterior renders, and perhaps especially Seoul for visualization pieces that we may be creating, the V-Ray IES light offers an extremely powerful, and easy to use method for adding real world lighting data. And so potential, extra realism to a scene. As we have with previous lights, then let's add an IES light to our scene by first of all, jumping into a quiet view. And then after coming over to the V-Ray toolbar, clicking to select the IES option. Now we do create this light type a little differently than some of the others, in that we need to left click, and drag in the front viewport in order to set the position of both the IAS light object itself and its target taking care of course, not to place the light inside any of the scene geometry if possible. After which we can then position those inside the camera view, and take a render. With what we get being a fairly plain looking low light effect that quite frankly doesn't look all that impressive, seeing as we also appear to be getting some very sharp CG looking edges to our shadows. What we have to remember with the IES light though, is that as noted, it has been designed to work a little differently than other lights in V-Ray. In that what we need to do now is locate the IES file that we want to attach to this light. An IES file in simple terms, being a digital profile of a real world light fixture, something that describes both the emission pattern, and emission strength of a specific light bulb inside a specific light fixture. Now, there are lots of free IES files to be found on the net with many lighting manufacturers, such as Ego and Phillips for instance, providing these for free. Often times along with a 3D model of the actual light fixture that they profile. Indeed, we can even find IES readers, editors, and creators online these days, such as the Real IES offering as www.found@real-ies.com. The file that I am going to be using though, can be found by first of all selecting just the light object from the Scene Explorer. And then after clicking on the IES file button in the modify tab, navigating to the Exercise Files, Scene Assets, and Photometric Folders. From there, we should be able to click to select the threelobeumbrella.iesfile. And if we render now, we do see a shift in both the illumination levels and in the light distribution pattern, though we still aren't seeing anything particularly interesting here. Watch what happens though, if we turn off the targeted option for the light, just for ease of use. And then use the align tool to move light to the point helper that has been set up against the back wall of our room. If we render a gain from our camera view, we do now see the complex lighting data that is found in the IES file at work, giving us a distribution of light energy, that would be pretty much impossible to achieve with any of the other light objects that are available in V-Ray. We are even getting realistic light decay or light fall off in the scene, because inverse-square decay is again built into the IAS light object. A faithful replica of real-world lighting data though, isn't always the end result that we are after in an image. Given that sometimes we are much more interested in the aesthetics of the light rather than its physical correctness. And so we may at times want to brighten our IAS light in order to make it more prominent in the shot, which is the case here. Something that we can do by coming to the lights intensity controls, sitting just below the color options, which we can also tweak if we want. And then using either the rescale option, which will essentially use the existing power information in the IES profile as a starting point from which we can then scale our light's intensity either up or down, or we can use the replace option where we can set a new intensity value such as 7,500 lumens, and then rerender. Although we do need to keep in mind that we are no longer being physically correct here in terms of the amount of illumination that the light is outputting into the scene. The end result that we get in terms of aesthetics though, may well justify that sacrifice. Add this functionality to a render with the GI engines enabled, and we can very clearly see the potential for both dramatic and realistic lighting effects that the V-Ray IES light provides.

Contents