Interactivity in the Arnold RenderView

- [Instructor] The Arnold RenderView is an interactive production rendering window to give you instant feedback when you make changes to the screen, such as the intensity of a light, or the position of a camera. Let's open up the Arnold RenderView. The recommended way to do it is to click in a viewport first. I'll select this camera viewport, and go in the menus to Arnold and choose Render. The Arnold RenderView window opens and renders the currently highlighted viewport at the resolution in the render settings.

Up here on the toolbar, we have controls, we can stop the processing by clicking on the red square, and we can resume by clicking on the red triangle like a play button. We've got controls for the exposure, and the visibility of alpha channel and so on. Over on the right, there's a panel with some of the same controls including exposure, gamma, and the color management settings. I'll set the gamma back to one and exposure back to zero.

By default, the Arnold RenderView will render with a number of threads, which is the available cores minus one. It leaves the equivalent of one core available for interactivity in Maya. You can change that behavior similarly to what we saw in the previous movie. To control the processor usage of the RenderView, go into the RenderView's Render menu, and under Save UI Threads, you can choose a number of threads to save, and if we leave it the default of one, then the RenderView will leave the equivalent of one core available for interactivity in Maya.

If you needed to run more programs at the same time you might want to set this to a higher number, but usually one is the optimal value. The Arnold RenderView is fully interactive. I've locked the transform attributes of the camera here, so it can't be moved. Let's demonstrate with the perspective camera. To load the perspective camera into the RenderView, let's first close the RenderView, and then click in the perspective camera to highlight it, go back into the menus and choose Arnold Render, and if you're still getting the camera shape one rendering, you can choose the persp shape from the pull-down list here, and now we're seeing the interior scene from the other side of the room.

If we move in the perspective view, the Arnold Renderview will update. We can use any of the standard Maya keyboard shortcuts or hotkeys such as alt and right mouse to dolly forward and back, and the Arnold RenderView updates automatically. There's also an option to ignore scene updates, which is this button up here, and if that button is on we get a slash through the icon, and that means now when I change my view in the perspective panel over here, it doesn't change the view in the Arnold RenderView, so I can move around here with alt and middle mouse, and the Arnold RenderView doesn't update.

Let's turn that back on again, and I've got scene updates re-enabled. Within the render panel itself, we actually have the ability to select objects. If I click on the tablecloth here, it actually selects that object in the scene even though paradoxically that object is one a referenced layer. I've got table layer over here, and it's referenced which means I can't select it in there viewports, but I can select it through the Arnold RenderView here.

Additionally, I can navigate directly in the Arnold RenderView. Go up into the window menu and choose 3D Manipulation, and now you're standard Maya keyboard shortcuts work in the Arnold renderview. Alt and middle mouse, and I'm able to truck left or right, alt and left mouse in order to tumble around the scene, and we can see it's updating in the RenderView and also in the viewport.

I'll turn that mode back off once again back in the window menu, turn off 3D Manipulation. If 3D Manipulation is off, then the hotkeys actually manipulate the RenderView in 2D, and here in the bottom I've got a value, which is the zoom factor for the currently displayed image, and if we want a one-to-one pixel correspondence between the rendering and the display panel here, we can click on one-to-one up here, real size, and now we've got a one-to-one relationship.

Each pixel in the rendered image is being displayed as a single pixel on the desktop. There's also a keyboard shortcut for that, which is O. There's good information down here at the bottom of the panel. If I move my cursor around, you'll see that update, and additionally, if we go into the pixel tab in the righthand panel and move the cursor around, we'll see more information. The most significant parameter here is luminesce, and that's shown here as lum, and here as L, and as I move my cursor around that value changes.

We don't want it to go above one, because if it did then the whites in the shot would be clipped, or cut off if the image is saved to an eight bit file format. Let's go back to the camera view here, and move the cursor around, and now I'm getting values near one up here. Once the rendering is complete in that area, then we can move the cursor around and be sure that the luminesce values are final values, and I'm not getting anything above one, so we're in a good place for the exposure for this shot.

Of course, we can make adjustments to our lights or materials in the scene, and they'll update in the Arnold RenderView. I can select a spotlight, for example, and that's the arrow over here. Select that spotlight, and in it's channelbox over here on the right, we can set it's intensity, and let's just set that to a value of zero, and we can see that the Arnold RenderView updated immediately. I'll set that intensity back to a value of one.

At anytime you can store a snapshot of the rendering in memory, and that's done from the little camera icon in the extreme lower right corner. Click on that, and we get a panel opening up, and we see snapshot one displayed there, and if we click on that we're actually displaying the snapshot. I'll set the intensity of the key light here to two, and then down here we've got a little eye icon. We click that icon then rendering resumes in the main RenderView window, and you can see now that that's overexposed.

That's only stored in memory. To save an image from the RenderView, display it in the RenderView window first. If I click on a snapshot then it displays that image. Go into the file menu and choose save image, and it'll save into the images folder of your Maya project by default, and that's how to use the Arnold RenderView for fast interactive production rendering.