1. The apple doesn't create shadow of the cup next to it. The shadow is created by the cup itself. But yes, you're correct that by the rim of the bottom edge of the cup, there's an ambient occlusion (or occlusion shadow), because ambient occlusion usually occurs on the rim of things. 2. You're correct that there's two light sources in that scene: one from the front right, and the other from the right. That's why you see two sets of cast shadows. 3. You're correct that the horizon line is on the top rim of the upper cup. 4. Defining highlight on a mirror or other reflected surfaces is kind of harder than defining highlights on the actual surface, because it follows a different set of logics. It's possible to do so, but I will say to stick to the reference for this one. 5. Indeed, tha value transition happens because when things are further away from the light source, they become darker. However, it doesn't only happen to big planes though. If you put another apple on the farther side of the scene, that apple will be darker than the apple that is closer to the light source. 6. Yes, as i've said in point number 2. 7. Technically, they're great rendering. However, artistically, you can try to blur the edges of the things that is adjacent to the shadows. As of right now, it seems to me that the edge is all sharp. This overall sharpness creates more of technical feel to the drawing. By blurring some of the edges, you'll create a more of artistic drawing, because our eyes naturally perceive edges differently than that is of a camera. Our eyes blur things that are in shadows or that are not in the focus.

Hi Natali, I'll do my best to help. Your rendering is impressive and according to me, you are on the right track. My Answers: 1) I understand that the theory behind occlusion shadows is that they are areas where light is almost completely (if not completely) prevented from reaching. If you are referring to the area with the blue rectangle, I wouldn't consider it an occlusion shadow. Occlusion shadows normally exist close to areas where two surfaces meet. For example, the area where the apple meets the table (OS), or where the white tallest box meets the table (the areas pointed by my pink/red lines - OS). If you check them out, you'll notice that they are nearly (if not completely) black. 2) I think you generally got the direction of the light source correct. I bet most would agree that if you hadn't brought it up, few (if any) would complain about that aspect of your artwork. According to the shadows, there does seem to be various light sources but from essentially the same direction - perhaps windows. You did the right thing the way you resolved it. You don't have to copy your reference exactly. Allowing yourself some artistic license to only capture the big picture is acceptable. 3) To identify the horizon line, I look for top planes and bottom planes (purple/ magenta boxes). If you can see the top plane of an object (even a bit), the horizon is above it. If you can see the bottom plane of an object (even a little), the horizon is below it. If you can't see either the top or bottom plane of an object, the horizon is somewhere between the top plane and the bottom plane. Since we can see the top plane of the tallest box it means the horizon is above it. But we can't see the top plane of the cup; therefore, the horizon is either at the same level as its top plane or below it. Conclusion - the horizon is somewhere between the top of the tallest box and the top of the cup (green box zone). 4) Reflective surfaces tend to get more reflective the further away they get from us. This is true for surfaces that are reflective but not mirrors or chrome (these tend to reflect everything as is). To understand reflectivity, you'll have to investigate further about the angle of incidence. The best I can give for now is that the area closest to the viewer is less reflective compared to the area further, like where the "cup" is. I recommend Scott Robertson's book "How To Render - the fundamentals of light, shadow, and reflectivity". You'll find all your answers and more in great detail and examples. 5) The value transition on the board in the background is the result of various elements - all available in its immediate surrounding. The source of light is a factor. The surface the objects are on is a factor. The objects themselves are a factor. Any other object in the environment that can reflect light is a factor. The interaction of light and all the elements in the environment impact their ultimate value. Also, the angle of incidence comes into play here. 6) You already brought this up earlier, and I think it is possible that there are various sources of light but generally from the same direction-ish. 7) As I indicated in the beginning, I believe you are on the right track. I'm not yet the expert I intend to be, but I can't say much against your artwork. One area I feel you may want to be more careful about is proportion. I don't know whether you did it intentionally but if you compare your work to the reference image, you'll notice that the relationship between the shorter box (the one with the cup on top) and the container in front (next to the apple) is not the same. In the reference, the shorter box seems taller than the container in front. In your work, this relationship is reversed - your container is depicted taller than the shorter box. Unless you did it intentionally, you may want to watch out for that. The last area according to me that I think you may improve on is reflected light. Your artwork has captured light and shadow areas quite well, but apart from the container in front (next to the apple), I don't notice much depiction of reflected light. I have noticed that most of your questions are about light, shadows, and reflectivity. Here are a few resources I believe will help: > How to Render - the fundamentals of light, shadow and reflectivity by Scott Robertson and Thomas Bertling (Book) > Ambient Occlusion - and Ambient Light for Painters (free YouTube video by Marco Bucci) > Mind-Blowing Realistic Shading Tricks (free YouTube video by Dorian Iten) > Fix Your Shading Mistakes - Egg Challenge Critiques (free YouTube video by Dorian Iten) I hope that helps and I wish you only the best

It's awesome you posted so many detailed, thoughtful questions! I don't think you need to apologize 🙂 I'll do my best to answer in detail in response: 1) I'm not sure which spot you're talking about. Can you post a picture with it indicated? Also, I'm not sure if you don't understand occlusion shadows in general, or if there's a specific area that you're not sure if it's an occlusion shadow. In general, reflectivity makes shadows less obvious—so a lot of occlusion shadows (and shadows in general) are more subtle in this photo. 2) (this also answers question 6) The lighting here is fairly complicated. From what I can tell there are 2 main light sources. You can see both of them on the apple—remember, highlights are really just reflections of the light sources. One of the light sources is really clearly seen in the yellow container in the front—it's a window that looks to be fairly large. It also looks like it's reflecting in a table—presumably the one the still life is set up on. So we can guess that that light source is largely frontal, but going up fairly high above the still life. It's a bit to side, but relatively close to straight on. We can tell that by its horizontal position on the yellow container. And we can know that a large window like that will produce a very diffuse light source. We don't have as much info about the second main light source since we don't have a clear reflection of it. But since it's presenting similarly in the apple in terms of size and softness, we can guess it's also a large, diffuse light source. Possibly another window above the one visible in the yellow container. I see hints of it in the curved top edge of the teacup, and I *think* that's what's reflected in the reflection of the yellow container. So, with two diffuse light sources you're going to have a few things in play. It's hard to glean from a photo, but there are likely some weird perspective things happening as objects cast shadows on vertical planes that have different tilts relative to the light source. Also, shadows from diffuse light sources get softer (more diffuse) the further they get away from the casting object. That may be doing some weird things as well. 3) That looks to be the case, although it's possibly a tiny bit below. I can see a *tiny bit* of an upward curve on the top of that cup. Also—the photo appears to be slightly tilted. I would expect the horizon line to be perfectly level. 4) Reflections within reflections do some unintuitive things (remember that highlights are really just bright reflections). As mentioned above, I *think* that's a reflection of the other light source we see in the apple. But its orientation is flopped vertically since we're seeing it in the reflection of the table. This is another thing that's hard to really wrap your head around with a photo. You'd probably be able to tell easily if you were there in person what's going on. With reflections in person, you can just move around a bit to understand, or wave your hand between things. With a photo, you're stuck guessing about reflections a lot. 5) Yes, it's because the cardboard is getting further from the light source. This effect happens with light sources that are relatively close. You wouldn't see this with a light source that's extremely far away and bright enough to still light the objects, like the sun. For smaller, closer lights, the strength of the light gets weaker the further away from the source it gets. It's called the falloff of the light. And in a lot of cases it happens faster than we expect. 6) See answers to #2 above 7) First off, keep working hard like you've clearly been doing, and asking tons of great questions. That's one of the best things you can do. Here are some other suggestions: - Work from life. The ability to interact with and inspect the scene lets you answer so many more questions than a photo. - Learn about edges and how to control them in whatever medium you're using—both the hardness/softness, but also just the drawing to clarify where things overlap. Spending time nailing the edges can make such a huge difference. For example—the edges on the left side of the teacup get kind of sloppy, especially where it overlaps the box it's sitting on. Make a clear decision where things start and end, and then make a clear decision how hard or soft its edge is, and how the softness changes along the edge. - Watch out for overstating the value of reflected light. A lot of reflected light is going onto glossy/reflective objects so it doesn't appear like the reflected light we see in diagrams. But it's all reflected light, and has lost some energy after bouncing off other objects. It loses more energy bouncing off matte objects than reflective objects. - I've found playing around with 3D software to answer tons of questions about light for me. But of course that's not for everyone, and it's time away from doing artwork. So might not be for everyone. But Blender is free, and its Cycles renderer is physically accurate (or at least enough for our needs as artists). I find it particularly useful as a teaching/learning aid. Hope this helps! Feel free to ask more questions—my favorite thing in life is teaching this kind of stuff to people who want to know it.