Okay. So now let's make a shadow pass, so we can use the shadow as a way to emphasize the shapes on our composition. So let me bring back the window and let's fill everything with white. Again, there's still going to be a slight difference between the light portion and the shadow portion of every object. But if you turn on the shadows such as I just did, what you have here is just the shadow information on your scene and you can change the months and the hours of the day, so you can have the shadow in the exact position you need. So I'm changing here the position, trying to find a good composition for my shadows and this is very important, as important as the placement of your actual elements. Because if my elements are well-placed and then I have a shadow that creates a wrong reading or creates a bad shape, I mean, I'm just basically throwing my composition away. So be very careful when you choose your shadow shapes because they are very important. So what I want here is to obscure a portion of our bridge. Let's do that with a piece of the rock which was actually floating. So we can create this magical feeling in our composition that there's just floating rocks around the environment, but we do have this cast shadow on the middle of the bridge. So let's go with this and let's turn on the hidden line mode, which basically turns this into a flat drawing, just line drawing, and if I hide my edges, I now have only the shadow information which is precisely what I want. So let's go to File, Export, 2D graphic, let's name it "CAVE-SHADOWS". So let's put here, SHADOWS, actually SHADOW is fine and let's export this. Let's just check that we don't need transparent background in this case because we are going to put this into the multiply mode in Photoshop, so the white will be transparent, but I don't want any strange artifacts so that's why I'm exporting with the white background within the image. Let's turn back our edges. I actually made a mistake and let's correct that mistake. So let's fill this with black again to create our alpha image again. So let's fill everything with the black and you'll see that when I exported this, I exported this image with a transparent background. But when you export with the transparent background in a PNG file, the transparent portion becomes black so it became all black. So what I'm doing now is, I'm going to export this image as a PNG but with a white background, which means non-transparent background. So I have my alpha channel, replacing our wrong file and that's okay. So now I can put this into Photoshop and easily select my entire composition separate from the background. Now I'm just going to create a gray scale version of my environment, which is also nice, not always used. Sometimes, I even create this layer but I don't use it in Photoshop, but sometimes they are very useful because you can select and create depth effects by manipulating this layer. So let's create it and let's see good difference between the areas in terms of tone. So I want you oppose dark versus light, so I can have it in a way that I can select better in Photoshop if I need to, but also retaining the gray scale aspect of it. Yeah, let's make this bridge lighter. Yeah, I think this works fine. We have enough separation, so let's export this image. But before exporting, let me get rid of my edges. So go to the edges and turn it off and now I only have the grays, which is precisely what I want. So go to File, Export, 2D graphic, let's call it "CAVE-GRAYS". Let's put it, GRAYS here. Let's make sure we have the transparent background turned off and let's export it. Okay. Let's also save our SketchUp file so we can change things later if we need to. So let's go to "Save As", let's select the correct folder, and let's save our file so we can access it later and make changes if we want to. So let's call it "Cave" and let's select it. So now it's time to go to Photoshop. So let's close SketchUp and let's import all the images we just created into Photoshop. So let's begin by importing the lines, and one thing is very important, never resize your images if you're going to superimpose them. So you import all the images because they will appear at the same size, then you can resize them altogether. So I'm just placing one image on top of the other, so let's import our clown pass. Let's import our, yes here, let's import our alpha channel. Now, let's import our grays. Okay. Let me pull this down so you can see better the layer arrangement. Now we have all the files we need to begin our painting. Let's just re-order these files so we can have the best possible reading of them. So now that everything is in place, let's select all the layers with the images and let's hit Control T, and by holding Shift and Alt, I can resize them from the middle, so I can re-position them all at the same time and they are all at the same place, so there's no mismatch in between the images. So I'm just trying to position it better in our composition, this looks nice. Now let's re-position some of the layers so we can have a nice organization in our layer. So I just put the lines on the topmost layer and change it to blending mode to multiply the alpha channel. Actually, the alpha layer will be on top of everything but turned off same as the cave clown pass. So we have the grays here and let's move it below everything, and let's turn the shadow layer also on a multiply blending mode so it can turn it on and off, and it just creates the shadows on our gray layer. All right. So this is looking pretty well, exactly as we want. So now if we select the clown pass layer and just let's change the tolerance here, so let's see. The higher the tolerance, the more colors you select. So if you have the clown pass layer selected, and you just click on the shapes, you see that you'll be able to select the colors that you previously established for each group. So for example, if I want the yellow portions for these rocks, if you uncheck contiguous, whenever you click on these shapes, all of them will be selected at the same time. But there's one thing actually. Remember that we had some differences between the light and the shadow on each color, we're going to correct that in a moment. But this makes our life so much easier because whenever we need to select let's say the bridge, it's just one click away. You don't have to use the lasso tool, you don't have to use any kind of like difficult selection tricks to select something. It's just one click and then everything will be selected, pretty much such as I'm showing you now. Also, if I want to select my entire composition and not the background, I just select my alpha layer and I just click on the black portion of it with one two and I have everything selected, separated from the background. So this is the perfect time to dive straight into the painting process. Let's do this into our next module.
