3D Producer - Reader

Transcription

1 D Producer - Reader

2 Lesson 0: Splines and NURBS surfaces Parametric splines Why re-invent the wheel? Instead of drawing splines by hand, you can use parametric spline to create all kinds of shapes, and of course animate them in the progress. Essentials Parametric splines can be converted into freehand splines by making them editable. Arc Circle Helix N-side Square 6 Star 7 Test 8 vectorizer Side 0 Cissoid Cogwheel Cycloid 5 The basic primitive splines offer you a wise range of shapes. Every single one of them has it s own unique use and will find their place in one of your scenes. Formula Flower 5 I-Profile Spline Mask Besides the parametric spline, Cinema D also offers a Spline Mask object that works like a boole for splines (). You can find the Spline Mask in Modeling Objects Menu. In contrast with the Boole object, Spline Mask works flawless, also with more complex objects ().

3 Essentials Diameter tolerance Lesson : Filament diameter tolerance When printing using any type of FDM printer, it s important to understand that the software controlling the printer calculates the extrusion volume based on the filament diameter, the diameter of your extruder nozzle and the extrusion speed (commonly referred to as flow rate in mm/s). In essence, your printer controls the volume of plastic that is pushed out of the nozzle by turning the extruder wheel and pushing a certain length of filament down the hot end (A). If you have an irregular diameter, the volume of extruded plastic varies and the software can t and won t adjust the extrusion length to compensate for the variation. Instead, it will keep on printing expecting a certain theoretical amount of plastic to come out. This is what we refer to as inconsistent extrusion. Ideally, your filament would maintain an absolutely constant diameter across the entire spool. However, in real life, due to the manufacturing process, there is always a tolerance within which the diameter will be maintained. The tolerance of a filament describes the variation in diameter that is present in the filament you use. For example, at Boots Industries our.75 mm filament features a diameter tolerance of ± 0.0 mm (B). Serious issues can arise from inconsistent filament diameter. A typical example is extruder failure, a condition where the extruder fails and no plastic makes it to the hot end. This can occur if your filament suddenly becomes too thin for the tensioning mechanism and there is insufficient pressure gripping the filament. Another effect of a decrease in filament diameter is that back flow could occur in the hot end (hindering plastic delivery to the head). The other extreme is when your filament s diameter is suddenly too wide and the extruder motor is not strong enough to push it through or it does not fit into the hot end opening. Another effect of an increase in diameter is that the extruder gear could shred the surface of the plastic leaving nothing to grip and stalling your extruder. A,75 mm The extruder wheel moves a certain distance to push the required volume to the hot end 0,5 mm B A B C,7 mm,75 mm,78 mm In all cases, extruder problems of this nature can be mitigated by a tensioning mechanism that applies and maintains the tension dynamically on the filament regardless of its diameter by using a spring. However, not all tensioners have this feature and will not guard you against gross diameter deviations. You may want to check our article on the POTs Calibration, it covers a common problem on the adjustment of your plastic extruder motor, correct adjustment is crucial for a good D print. Typically, when looking at filament tolerance, the gold standard across the industry is < 0.05 mm. Working closely with our manufacturer we found that it s very hard to go lower than that and maintain consistency across the full length of a spool. When you purchase a new spool you can use a micrometer to measure the diameter at several places and insure that it meets the advertised tolerance. A Max. Diameter decrease (0,0 mm.) B Ideal filament diameter (,75 mm.) C Max. diameter increase (0,0 mm.) C Filament Roundness When making contact with the extruder wheel, the filament will always suffer some compression due to the extruder wheel gripping the plastic. This will, in fact, reduce the roundness of the filament but is consistent across the entire spool so will not really affect print quality. That being said, the consistency of filament roundness across the entire length of the spool is still important. This is because filament that suddenly loses its perfect round shape and becomes oval can lead to extruder failure in the same way that increasing or decreasing filament diameter does. Spool Diameter A thin filament could lose contact with the extruder wheel C If you are buying filament it s because you intend to use it all. We ve tried a lot of different suppliers and came across different types of spools. We found that some spool designs can compromise the usability of the material. When using spools where the inner diameter is relatively small (<00 mm) we found that the tightly wound plastic is harder to unspool. This can be affected by the temperature of the plastic when it is spooled by the manufacturer. Some will go through the extra step of letting the plastic cool a bit before coiling. Nonetheless, it s important to remember that most extruder designs require the extruder to pull the filament off the spool. As such, when you reach the end of a tightly coiled spool, the filament becomes harder to unspool and the extruder gear can start to slip and strip off your filament. This situation is usually fixed by increasing the extruder tension, but with too much tension the roundness of the filament can start to become compromised (too much pressure is applied on the filament and it becomes somewhat oval). Thick filament could ruin your D print by clogging up the nozzle, or shredding the filament. To maintain a constant setup and minimize extruder strain, we recommend a spool with an inner diameter greater than 00 mm. Of course, you don t want to have a spool with an inner diameter that is too large as it is more expensive to ship and store. Each supplier has their own policy, we simply wished to discuss spool diameter as a parameter of interest when considering plastic filament for D printing. Source: 58

4 Lesson : Material channels Essentials Refraction Refraction can be explained as follows. A light ray in a vacuum has a certain speed. When the light ray hits a more solid material then air, the speed of the ray decreases. The light ray will bend. This will cause the effect that a object behind the transparent surface will shift from it s original position (). If a refraction index is to high, the lightray will bounce back from the surface and the refraction will turn into a reflection. The degree of bending is determined by the density and purity of the material hit by the light rays. A list of common material refractions can be found in the Help files or the table below. Vacuum xº bend by Refraction Index Glass Vacuum A higher refraction Index will increase your render times significantly Acrylic Glass,9 Agate Air.000 Amber.550 Amethyst Benzene.50 Common salt.5 Crown glass.50 Diamond Emerald Flint glass.6 Glass Ice (H O).0 Jade Jasper.50 Obsidian Onyx Quartz.550 Ruby Sapphire.760 Sugar.560 Topaz Vacuum.000 Water. Blurriness (dispersion) The Blurriness parameter decreases the sharpness of the materials reflection. The effect comes with a heavy price-tag. Render times can easily tripled. If you still want to use the blurriness effect, you might want to change to the Physical Render instead of the standard render. The physical render is created to deal with samples, and this effect is right down it s ally. ) No bluriness (0:5) ) 0% blur. - acc. 50% (09:8) ) 50% blur. - acc. 50% (:5) Reflectance So, this were all the theory blends with the practice in a witches cauldron. Direct Illumination, Indirect illumination, diffuse reflection, ray traced reflection, specular reflection and anisotrophic reflection. What does these mean, and how tho they work for you? It comes down to one question; why on earth do we see things? The answer is pretty much out of this world, isn t it Amaterasu? 65

5 Lesson : Light and lightrigs Essentials -point light setup (lightrig) ) Subject ) Key-light (catch-light) A) Hard-key B) Soft-key C) Key in front of camera A ) Fill-light B ) Backlight / Ambient light C 5 Key-light + backlight ) Key light ) Fill light ) Rim light / back light ) Four light composition Lighting variations ) Hard key 5 ) Colored key and fill ) Key light pitch angle ) Cookie / Gobo 95

6 Compositing Lesson 6: Multipass rendering to After Effects Image layers (/) Atmosphere Volumetric effects like fog, visible light and hair. Atmosphere Multiplied This layer is used to mask the scene if volumetric affects appear in front of other objects. Post Effects Post Effects like Glow and Lens Flares. Also Sketch and Toon can be rendered as a post effect. Material layers The Material Layers are not as often used as the image layers. They Material Layers provide extended control over the material channels of all materials used in the scene. The material Layers have no real relevance in Cinema D. Material Color Material Diffusion Material Luminance Material Transparency Material Reflection Material Environment Material Specular (Color) 8 9A 9B Material UVW Material UVW shows the surface direction of the mesh in RGB color information. When applied on only flat surfaces, this information can be used to map footage on the surface in post-production. I personally prefer the use of Null s and Solids, since this information is easily saved and does not require re-rendering when something is amiss with the D positioning. Material Normal The Material Normal can be used to create a Normal Map of an entire scene. A Normal Map (9A) is a image that uses RGB values to simulate depth and direction in materials without actually deforming the mesh. The principle is about the same as a bump map but more accurate when it comes to lighting. Normal Maps can be used in the Normal Channel (9B) of a Cinema D Material. Since version, you can also use the Normal Map in Displacement Channel (9C). 9C 6