Creating a sun positioner - 3ds Max Tutorial

- [Instructor] The sun positioner makes it easy to set up photometrically accurate exterior daylight. You can place the sun anywhere in the sky, either manually or automatically, with geographic and calendar data. This makes is easy to quickly light a scene, for an animation for example, or conduct lighting studies for architecture. The sun positioner is categorized as a light, but it's really just a manipulator or gizmo to control the parameters for an environment map, the 3DS Max physical sun and sky map. When you create a sun positioner, the environment map is created and assigned automatically. Physical sun and sky will render correctly in the ART and Arnold renderers, and should also work fine in any other physically-based renderer. I got a scene set up to illustrate exterior daylighting with a sun positioner. Let's open that up from the file menu. File open, we're taken to the current project scenes folder, 02_02_sun_sky.max, and click open, and you'll probably get the file load units mismatch dialog, because this scene is set up so that a unit is a meter rather than the default of inches, and this case we do want to adopt the file's unit scale, and click OK. And once that scene loads, the system unit scale is set to meters. However, if you reset, the system unit scale will be set back to inches in this case, because I have a maxdark.map document in my current project scenes, and that's the default template for a new scene and it's setup for inches. To demonstrate the sun positioner let's set the current renderer to ART, go over to the main toolbar and click on the render set up button or use the keyboard shortcut which is F10. Change the target over to active shade mode, and set the renderer to ART renderer. Make sure the view to render is physcamera001 and click the render button. And we'll see what this looks like with default lighting and no sun positioner, just to get a baseline of what this looks like with no lights. Okay well close that active shade window, close the render setup window. And create the sun positioner in the create panel. Go to lights, photometric, sun positioner, click that, go over to the top view port and somewhere near the camera click and drag, and you're defining the radius for a compass rose. Release the mouse to set the radius. Then without holding down the mouse button, move the mouse and now you're able to rotate the compass rose. You just want to rotate it so that north is pointing upward in the top view port. Click to set that rotation and then move the mouse again without holding down the button, and you're setting the distance of the sun from the compass rose. When you have the distance you want just click, and now that sun positioner's finished. Right click to exit the tool and with the sun positioner still selected you can go to the modify panel and access its parameters. So that the sun appears in the correct position in the camera view port here, we can move the compass rose to the position of the camera. We'll do that by snapping to pivots. So go up to 3D snaps and right click and make sure that you're snapping to pivots. The default is grid points, so you want to turn grid points off and pivot on. Close the grid and snap settings dialog, enable 3D snaps, grab the move tool, and click in the center of that compass rose, drag over to the camera until you snap to its pivot. Release the mouse, and you might want to check that in the top and left view ports by just zooming in a bit, zoom in on there, just make sure your snaps to that camera and if that all looks good we can turn off 3D snaps. Now the position of the compass does not affect the lighting or the environment. And this is merely so that the sun position in the camera view port will match the rendering. If you want you can use a position constraint to lock that compass to the camera. I'll leave that as an exercise for you, but don't use a parent child hierarchical link because we don't want the compass to inherent the rotation of the camera. That would cause the sun to move when the camera rotates which is not normally something we want. Alright we are ready to do a test render now. So let's choose physcamera001, and click active shade. Here's the result of an ART rendering of the sun positioner with default settings. When we created the sun positioner, physical exposure control was automatically enabled. And unlike previous versions of 3DS max, when that happens the user does not get a prompt. So we weren't informed but physical exposure control is enabled so let's check in on that in the rendering menu, exposure control, and we can see physical camera exposure control is active. And we can see what happens if we turn exposure control off, the physical sun and sky environment is photometrically accurate, so it is very very intense light. And without any exposure control we get an almost pure field of white. I'll set that back to physical camera exposure control with default parameters. Let's go into the sun positioner parameters, I'll close the environment and effects dialog and select the compass rose in one of the view ports. And if the active shade changes then you can just right click on physical camera once again, and or relaunch the active shade window. Now if the sun positioner parameter's displayed in the modify panel, you've got the basic one such as the distance and that's not affecting the lighting. But we can change the direction of north or the size of the icon here, just as we could interactively when we first created the sun positioner. There are three modes of operation down here, we'll talk about two of them. We have date, time and location, in which you can just plug in geographic and calendar data, and do a lighting study. There's also manual mode where you can set an azimuth and elevation or altitude. The most basic thing we can do is change the time of day here just by clicking on the time hours field. We can move the sun around in the sky. So I set this to 19 hours, we're getting dusk. Very cool. You can also set the date and also the location on the planet. We have location on earth down here near the bottom and it's labeled San Francisco, California by default. We can click on that and we get a little map. We can choose some location on the map. Somewhere in Arizona maybe. We've got Yuma, Arizona, let's choose that. And then we've got the latitude and longitude for that position on the earth, as well as its timezone. And we can set a certain month or time of day. Click on the month and we can see what this look like in July month number seven. As we adjust the date, time and location, the horizontal coordinates down here at the very bottom update automatically. If you want to set the azimuth and altitude manually just switch it over to manual. And I've got a low altitude, and I'll adjust this azimuth and cause that to make the sun swing around so we can view the results in the top view and the active shade, as we adjust the azimuth value up or down. And at some point I should actually have the sun shining into the camera lens. And this is why it's helpful to position the compass rose at the camera location because now we've got a clear view of where the sun should be in the sky. It's right there. Let's quickly change the exposure controls so that we can see exactly where the sun is in the sky. Click in the camera view port to deselect the sun positioner. And you're no loner entering any values into the modify panel, open up the exposure control window with a keyboard shortcut which is eight. And let's just make a couple changes here. I want to have global exposure control so I'll turn off the check box labeled use physical camera controls if available. Turn that off and now I can change the exposure value over here, let's set that to a value of 15. And now we can clearly see the sun disc, and it's in the same position in the sky as it is in the view port. And that's why we position the compass rose right on the cameras pivot point. That's the basics of setting up physical sun and sky with the sun positioner.