Fergy Posted March 28, 2011 Share Posted March 28, 2011 I've got four questions for rendering that I'm stumped with: First, I need a little clarification about HDRI backgrounds/lighting. What do the names of the different files refer to? Are they all just randomly different, or is there a pattern to them? Second, when using HDRI for viewport lighting, I really like the results, but I'm not getting shadows from the objects cast on the "floor" object. I've tried different textures for that object, but I'm not getting anything, so the rendering looks fake at that point. Do I have to include at least a couple of additional directional lights for that purpose? Third, what is the orientation of the HDRI lighting in relation to the viewport, or more precisely, the camera that creates the viewport? Is it a dome with a series of lights on it, or how is it truly working? And lastly, when rendering an interior scene, how do you display a ceiling object and still use directional lighting to light a scene? For example, how would one render a camera view of the interior of an arena, where you want to show the ceiling, but the model requires lighting to render in a realistic manner? Thanks in advance, Quote Link to comment
Vectorworks, Inc Employee Tamsin Slatter Posted March 28, 2011 Vectorworks, Inc Employee Share Posted March 28, 2011 Hi Fergy Yes, you probably do need to add a directional light to create shadows on the floor, but it depends on which HDRI background you use. Try turning down ambient light a little - that may have some effect. The orientation depends very much on the HDRI you are using. There is no hard and fast rule, so just experiment. Create a floor and place a sphere on it in a new file. Render in Top view with different backgrounds applied and you can guage the orientation of the HDRI relative to the screen. To get a directional light to light a scene in what is effectively a closed box, turn off Cast Shadows for the directional light. It will then pass through the walls/floors/ceilings. Hope that helps! Quote Link to comment
Kaare Baekgaard Posted March 28, 2011 Share Posted March 28, 2011 (edited) If you wish to have shadow footprints from furniture in an interior scene, you can supplement the non-shadowcasting lights with a shadowcasting directional 10-20% light comming from above at a 90? angle - and then give the ceiling a texture, that does not cast shadows. (Assuming, that there are no structures above the ceiling). Shadowcasting can be disabled for any texture in the texture dialogue. For viewports be sure to check in the OIP, that the HDRI is actually doing the lighting. It isn't always so by default. Edited March 28, 2011 by Kaare Baekgaard Quote Link to comment
Fergy Posted March 28, 2011 Author Share Posted March 28, 2011 All of this is being done inside of SLVP, not in the design layers. I've set up the scenes use HDRI in the Layer Lighting Options dialog. What I find strange is that sometimes the HDRI casts shadows, and other times it doesn't. I just can't figure out the method to the madness. I hadn't thought of giving the ceiling objects textures that don't cast shadows; I was just leaving them as primitives and using their attribute colors at the moment. Quote Link to comment
Fergy Posted March 28, 2011 Author Share Posted March 28, 2011 Hi Fergy Yes, you probably do need to add a directional light to create shadows on the floor, but it depends on which HDRI background you use. Try turning down ambient light a little - that may have some effect. The orientation depends very much on the HDRI you are using. There is no hard and fast rule, so just experiment. Create a floor and place a sphere on it in a new file. Render in Top view with different backgrounds applied and you can guage the orientation of the HDRI relative to the screen. To get a directional light to light a scene in what is effectively a closed box, turn off Cast Shadows for the directional light. It will then pass through the walls/floors/ceilings. Hope that helps! Thanks Tamsin, But what I want it to cast shadows with the directional lights? That's the current problem. I just want to be able to set the height of the effective emitter for it, so that I can set that emitter below the ceiling height. Spotlights don't work, because they emit as a cone. I'll play around with the HDRI files and see. It's just frustrating, because some of these renderings take quite a while, especially once I start adding in a lot of textures and other rendering lights. Quote Link to comment
Vectorworks, Inc Employee Tamsin Slatter Posted March 28, 2011 Vectorworks, Inc Employee Share Posted March 28, 2011 In that case, Kaare's alternative option of creating a texture which does not cast shadows will do the trick. Quote Link to comment
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