Alias Tutorial Boyd -Web

Sketchinga Car

You might have read a similar tutorial before, but this is a revamped version to give you a sense of what is accomplished in each step. This is a SIMPLE guide to help you get started in creating a car in AliasStudio. As usual, start with a simple doodle. You can choose any default pencil or brush, it doesn't have to be some fancy tool. Be as creative as you can, you don't have to worry about precision at this stage.

Next we can flip the layer in the Canvas Layer Editor. This is done to check the perspective of the sketch. Also you can compare which perspective looks better, you don't have to be restricted to be viewing in the way you sketched it. It is also a nice idea to rotate it a bit to give it a dynamic look.

Once you've found a good looking position, create a new layer and start refining your sketch. Make sure you lower the opacity of the sketch layer so it doesn't get in your way. You can choose any tool that you might think that gives you a refined stroke. Just go over the sketch with it and create more defined strokes.

That's all for sketching, let's move on to painting. Generally, I like to use 2-3 colors for the background. This helps set an overall mood for the painting. By using a limited palette creates a harmonic atmosphere giving an ambient feel for the painting. A little trick I like to use is that I recycle the colors that I've chosen for shading in the next few steps.

Lets apply a shadow pass to the painting. On a new layer, choose a solid dark coloured brush. You can play with the opacity to find a good shade for the painting, I like to use a 40% opacity brush. Just go over the areas that need a good shadow.

Lets apply a light pass to the painting. Again, like before, on a new layer choose a light colored brush. With the same settings you can go over the highlights of the painting. It's always good to know the direction of light that is hitting the car.

Next, on a new layer, lets apply some shadow curvatures. Using an air bush, you can create volume of the car by going through it with long strokes. Then use the hard eraser and erase back parts to give a fine curvature to the car.

Next we look into creating details. Using a pencil or a small brush, you can add strokes to bring out some details on the car. This can be applied to such areas as head-lights, or vents. Again, you can play with the opacity of the tool to get the desires strokes.

Finally, you can add some highlights. While using a white pencil on a new layer, we can add strokes to parts of the car that you want to give more emphasis on. This also creates the shine you would see on a clean car.

Last but not least, sign your painting. And we're done!

NaturalSurfacing Part 1

Introduction Part 1 In this series of demonstrations we will be exploring a variety of surfacing techniques. The particular technique I’ll be focusing on however, I’ve heard called by a variety of terms; from “pulling CV’s”, to Direct Modeling to Natural Surfacing. The first term is the most obvious, but the last seems the most, well, natural and describes the technique in the way I like to think of it. The key to much of what I’ll show is that I’m using very few curves to create surfaces and as a result, very few surfaces. The goal is to create very fluid forms without some of the frustrating results that can come from stitching together little patches. I find that the more techniques I have under my belt, the more ways I have to look at, and ultimately solve, a given problem. I have used this technique in some capacity on most every product I’ve ever worked on. It’s one of the more unique approaches to form development that Alias Studio has to offer, and one that can drive even to most talented solids modeler crazy trying to replicate (this can be both good and bad depending on who you work with and your downstream process). As a platform to illustrate the techniques, I’ve chosen a sports watch much like the ones produced by Nike, Suunto or Polar. The reason for this is a couple fold; the forms tend to be

dynamic and fluid, but more importantly, because of the LCD display; a rigid component, they also need to be a controlled form and not just crazy shaped because they can be. This is not meant to be a “how to build a watch tutorial” but a demonstration of techniques that could be applied to any product design. Good Curves make Good Surfaces The watch that I have chosen to create will have a circular display. By imposing this requirement on the demonstration, I will be able to offer solutions to creating an organic form that incorporates non-organic elements. The easiest way to establish the core component will be with a revolved surface; and that starts with a curve. The curve shown here has as few CV’s as will allow to create the shape I want. Being conservative with CV’s will be a common theme throughout the demo. The reason for this is that surfaces, like curves, use CV’s to define their shape and the more CV’s there are, the more chance for lumps or flats there are. I can be very meticulous about my CV placement and will often build a model several times to find ways of getting that CV count down. This curve has 3 CV’s at the start that let me define the top crown, 3 CV’s at the end define the bottom crown and two at the perimeter that allow me to control the peak radius at the edge. I should also mention that this is a 5th degree curve. I find them the easiest to work with for this type of modeling exercise. They stay smoother than 3rd degree curves and are more responsive than 7th degree curves. Incidentally, the minimum radius that is shown in the curvature plot is close to what I know will be the final thickness of the watch’s strap. It’s never too early to plan ahead.

The Revolve The biggest challenge when working with revolved surfaces and spheres is the “pole”. This is where all the CV’s and isoparms come together. If you’ve ever picked apart one of these surfaces, you’ll know that the poles are a nasty dirty mess. There are many things all piled on top of on another. The problem with poles are that trying to extract surface direction from them can be difficult. The UV directions are heading everywhere and nowhere at the same time which will give tools like Align or Blend Curves nightmares in trying to resolve the situation. I’ll go to great lengths to not have to deal with this type of thing.

The revolve in this case will be most useful to us as an underlay as we build the rest of our model.

Prepping the Revolve Here, I’ve done a few things: I detached the revolved surface such that only a quarter of it is left; I’ve snapped a line to the two middle isoparms; projected this line onto the revolve along the X axis and then trimmed it. The end result, is one side that has the desired cross-section profile, and two edges (interrupted by the trim) that are a single span each. The fourth edge (the result of the projected curve on surface and trim) won’t be used in the following steps. It’s a trimmed edge, and building from trimmed edges are generally something I’ll avoid until very late in a model build.

Drafting 'Stuf' Surfaces I often make little temporary surfaces to build from. I’m not sure if they have a proper name, but I call them stub surfaces. Usually they get deleted after they serve their purpose. These particular surfaces will be used as guides to build what will become the main body of the watch or ‘Master’ surface. They were created using the Draft tool (one of my favorite tools) in each the X and Y directions. Notice how the isoparms of the Draft surfaces match the isoparms of the reference revolve.

Creating the Master Surface Here I create the start of the Master Surface using the Birail tool. The generation curve references the edge of the stub surface created from the untrimmed edge of the revolve. The rails reference the other two edges with one span each. Again, notice that (as long as ‘rebuilds’ are off in the Birail tool) the edges of our new surface reflect the span structure (and thus CV placement) of the stub surfaces which in turn have inherited their structure of the revolved surface. So why this step? Well, we’ve effectively built a surface that has much of the character of the revolve, but minus that nasty pole. As a bonus, we now have a surface that is 5th degree in both U and V directions - as opposed to the revolve that would have been 5th degree in one (based on our input curve) and 3rd degree in the other (which is just the way a revolve is built). The ultimate goal, however, is for the Master Surface to hug the revolve as closely as possible. Let me note though, that while using the trimmed edge on the revolve (i.e. 2 gens and 2 rails) may have resulted in a tighter surface, building from a trimmed edge will always interject extra isoparms into the newly constructed surface. The point being is that I am trying to get the CV placement and structure in place before I worry about form. This is just the beginning...

Quad Symmetry AliasStudio has some nice two-way symmetry tools in the Layer Symmetry option. Just put some geometry on a layer, turn symmetry on and you have a ‘live’ mirrored reference. Any changes you make to one side, are made to the other. But what about 4-way symmetry (or more)? Fortunately we can use ‘instances’ to achieve a similar effect. Here, I’ve started with my railed Master Surface and then using the Duplicate Object Options, I enter -1 in the X scale parameter (to get the mirror) and change ‘Copy’ to ‘Instance’. An instance is like a virtual copy. You can’t modify the instance, but you can modify the original from whence it came- thus aping the ‘live’ effect that Layer Symmetry offers. In this particular case, I’ve combined an instance with the layer symmetry to get 4-way symmetry. There is only one surface in this scene that can actually be modified, but all four quadrants will change when it’s tweaked.

Quad Symmetry Example Here is an example of the previous concept in action. I’ve tugged on one CV and all four surfaces have been modified. This set-up allows a lot more flexibility in the way I work and reduces errors resulting from not seeing the mirrored half of an object and losing tangency as a result.

A CV Primer Before we start modifying our shape, I wanted to establish some ground rules for manipulating CV’s on a surface. I like to think about CV layouts in terms of rows. The CV’s that exist at the edge of a surface define that surface’s edge profile. If the CV’s are in a straight line, the surface’s edge will be a straight line. This is the ‘Positional Row’.

The next row in, the second row of CV’s, are the ‘Tangential Row’. This row defines the ‘vector’ at which the surface terminates. If all these CV’s are aligned in a horizontal plane relative to the ‘Positional Row’ then your surface will be tangent to a horizontal plane adjacent to the surface’s edge. These two rows are well within a human’s ability to control manually. The next row in, the third row of CV’s, are the ‘Curvature Row’. Without getting into a whole discussion about ‘what is curvature continuity’, we’ll just say, in most situations, it’s improbable and impractical that anyone would model two adjacent surfaces to curvature continuity without the aide of computer control. The math is just too great. There are two situations where this isn’t true. The first is; that to be curvature continuous with a flat plane requires that the first three rows of CV’s be in that same plane. The second is when dealing with symmetry. By definition, a surface mirrored about it’s edge will be curvature continuous to itself along that edge (assuming the edge was at least perpendicular to the plane of reflection). It may not be pretty, but it will be mathematically correct.

Using an Underlay Let’s start sculpting. I’ve brought back the original revolve in it’s entirety. We will be using it as a guide to help us shape the Master Surface. To facilitate this, I’ve colored the revolve a different color than the Master Surface. You will immediately notice that the revolve shows through in areas, but in a fuzzy, noisy kind of way. This is an artifact of shading in 3D programs. It’s probably a bug, but I’ve never seen any 3D software that doesn’t do this, so I’ve taken to using it as a feature. The premise is simple, when two surfaces have nearly the same topology, the computer can’t decide which one to bring to the forefront to shade first, so it shades them both and makes this noisy pattern. In this case, this is how we’ll know when our Master Surface is approaching the right shape. We see the noise at the edges of each quad because they currently use the same CV placement at those edges. The rest of the surfaces are quite different from one another so we don’t see anything other than the front most/outer surface.

Placing the Strap Before we get too carried away with tweaking the shape of the Master Surface to match the revolve underlay, we have to do a couple of things first that will make our situation worse before we can make it better. I’ve placed the start of the wrist strap in the model. It’s placement in 3D space is based on an ellipse that represents a person’s wrist. I use a 60 mm x 40 mm ellipse. The strap is placed tangent to that ellipse so that the straps extend out at about 30° from vertical. This will vary on your design and manufacturing method. The profile of the strap is built from a duplicate curve that has been copied off of the original revolve. This is important since we want our number of CV’s and spans to be identical to the Master Surface.

Insert Isoparms If we were to just align the Master Surface to the strap at this point, most of our CV’s that define the median profile would be swallowed-up by the alignment resulting in quite a loss of our overall shape and the need to rebuild and tweak more than necessary. Anytime you move a CV, it has ‘influence’ both upstream and downstream from itself. The higher the degree of the curve or surface, the more broad this influence can be. By inserting two isoparms (Object Edit > Insert) close to the edge of the Master Surface we gain a couple new rows of CV’s. We have the existing Positional row and now new Tangential and Curvature rows close to the edge we’ll be aligning. We’ll still lose some shape due to stretching, but much less than we would have if we had just let the original rows to become aligned with the strap.

Aligning the Strap Next we align that edge with the new isoparms to the edge of the strap surface we made earlier and we have the start of our fluid watch shape. The CV rows that were so close together in our previous step are now spaced far apart and make an elegant transition into the head of the watch. While we still have construction history for the alignment, we can move the CV’s around. They will snap back to the next closest position in space that still meets the requirement of the align, so if your CV’s are too close or too far, a quick manual adjustment will get them looking right. As an aside, I find that the “Align 2008” works better for this type of modeling approach, where as the new Align tool in AliasStudio 2009 works great on trimmed surface edges.

Align Result Before we start tweaking, I wanted to show what the surfaces look like after the strap transition alignment. In earlier stages, the median profile was much closer to the underlay and now it is very different. We could have added more isoparms to the surface prior to the align, but that would have also meant more CV’s for us to deal with, so in the interest of CV conservation, I didn’t add any more isoparms than I needed at that point.

First Tweak After giving the CV’s a good tweaking, our shape is much closer to the revolve than ever.

I wish I could show you every step along the way, but each CV move is subtle. I tried to capture the development of this project at stages when there is something to show or before I do something drastic. I also wish there was a specific ‘this or that’ I could share in regards to actually moving the CV’s, but it really comes down to practice and patience. This is not a terribly fast method of sculpting. Well, I take that back - it can be - in fact I sketch this way quite often, but for final, production-ready appearance surfaces, it’s tedious at best. It is an art form of sorts. Generally though, here are some tips. The CV Move Tool (at the bottom of the control panel) has three modes, NUV, XYZ and “Slide”. XYZ functions like the regular Move Tool under the Transform menu and moves CV’s along any of the world space axes. NUV moves CV’s either along the surface or perpendicular to it. Lastly is “Slide”. This last mode adds a little move widget to selected CV’s which allows you to move the CV along it’s connected ‘hull’. This is great for moving Tangential Row CV’s when you don’t want to break their tangent vector. For all the other CV’s, I usually use the NUV and XYZ modes. Keep in mind that position of the tangent row CV’s and how they need to stay in the same plane as the Positional row.

Add Density A few steps ago, I commented about not adding isoparms to control the shape of the Master Surface, now I will add isoparms. Why now, but not then? Because with less CV’s to deal with, I was able to rough-in the shape faster than if I had more. The median profile would not have moved as much after the strap transition alignment, but I would have also have more points to deal with when I was trying to shape the other parts. With practice, these decisions become instinctual. Ultimately, everybody works a bit differently as well, and there is no wrong answer - just ugly surfaces...

More Tweaking We are getting closer now. The shading noise is becoming more diffuse and uniform. We are also seeing the polar pattern of the revolve show through the Cartesian pattern of the Master Surface.

More Tweaking, Bottom Edition I haven’t shown the bottom side of the watch yet and for those curious, here it is. It’s looking much like the top at this point. Similar noise pattern. One thing that is difficult to convey in still images is how the noise changes based on zoom level. You can sometimes gauge how similar or dissimilar surfaces are by dollying the camera in an out and watching the noise pattern change throughout the zoom.

Project Reference Curves Often times, a visual inspection of the surface won’t be enough. In this case, I plan to have some elements of the design that will need to perfectly mate together. I am assuming that this watch will have a ground glass lens. Because of the way watch crystals are made, the lens will have to be a perfect revolved section. Fortunately, we started with one of those. But how can I be sure the Master Surface and the revolved section will meet perfectly at the adjacent edge? By projecting a line (in this case a circle - or two) onto both, I now have a common reference point by which to judge.

Deviation Measurment

With both the revolve and Master Surface sporting projected Curves on Surface, I can now add a deviation measurement using “MinMax Curve-Curve Deviation” in the Locators palette. I can see that one of my circles is off by only 0.0766 mm but the other is off by 0.2144 mm. I would prefer to have these values below 0.01 mm - a value that will be far below the manufacturing tolerance of the parts. We still have some work to do.

Tweak Result With some additional work, our projected curves are within acceptable tolerance of each other. Again, there is no magic trick, just persistence. One of the things that I try to do while CV tweaking is to maintain uniformity of each of my rows - both along the U and the V of the surface. I generally don’t make huge adjustments to just one CV, but rather ‘creep-up’ on the desired form by moving each CV just a bit. I usually find working in a radial pattern out from the most misaligned portions a good approach. This prevents the tendency to over-adjust one CV and then over-compensate with CV’s surrounding it. Think of the array of CV’s around your object like a cage that floats just off the surface. This cage really defines your shape and there fore shouldn’t be much different. Lastly, and most importantly, save often. Save iterations. Definitely save before you insert a new isoparm. I will sometimes have dozens of files that have each been incrementally saved as I go.

Expand Instances Every good story has at least one good twist. This one will have a few. Using “Expand Instances” will convert the selected instance from a virtual copy into real geometry. With this relationship broken, any changes I make to one side, will no longer be reflected in the other. I have also turned-off the layer symmetry option. No instances. No layer symmetry. What could be next? Something decidedly unsymmetrical, I suppose...

The Twist in the Story So far we have been working with geometry that mirrors itself across multiple axes. This has kept the demonstration fairly straight-forward and digestible, I hope. But in the interest of creating a truly dynamic and fluid shape, we are going to give this product a bit of that “hurricane” aesthetic common to sport watches. Here, I grab the CV’s that make-up the majority of the watch’s head and rotate them about the Z axis. In case you were wondering, the head in the final model is rotated 27 degrees. I did this by typing the values 0,0,27 after selecting the rotate tool. Be sure to be set to ‘relative’ mode or CV’s will move in unexpected ways. I will then grab the remaining CV’s and twist them over and downward to smooth out the strap transition again. Think about you CV’s in blocks or masses. The three rows of CV’s at the end of the strap would be good example of CV’s that should be moved as one ‘unit’. The head CV’s are another.

Twisted Result Boom. That’s quite a bit different from where we started from. It’s still pretty rough, but in the next part this series we’ll be looking at a variety of techniques to continue tightening-up the model. I hope this shows some of the advantages of working with this method of surface development. If this model had been constructed using several surfaces knitted together with little blends and transitions, it would have been very time consuming to make a broad sweeping change like this. We are far from done, so see you in Part 2...

About the Author Joshua Maruska Principle Design Scientist : Teague As the Principle Design Scientist at Teague, Joshua is responsible for ensuring the technical integrity of products and projects developed in the Teague Product Studio. Joshua also plays a pivotal role in cultivating the company’s creative culture; assisting diverse teams of talent in meeting core design objectives. Designing since 1993, Joshua has worked with some of the world’s leading brands including Motorola, Hewlett-Packard, Thomson, Nike, Panasonic, Boeing, Microsoft, Starbucks and Samsung among others. His contributions to the industry have been recognized in the form of numerous awards including Red Dot, iF Award, Good Design Award and IDEA. www.teague.com joshua.maruskadesign.com

Refractiveindexes of some popular gemstones

Refractive indexes of some popular gemstones

Here are some refractive indexes and Moh's hardness values for some common gemstones that you might be modeling for jewelry design. The refractive indexes can clearly be used directly in most of our products, since most have a field for the refractive index of materials. Moh's hardness values are a little more subjective. They can help to indicate the fall-off in the specular highlight on something like a cabochon gem. Think of an opal, which is very soft: the highlight doesn't have the same brittle glassiness that a polished diamond would have, for

example.

Rendered model of diamonds.

This information has been extracted from Gemstones of the World, by Walter Schumann; Sterling Publishing Co. Inc., New York 10016, and N.A.G. Press Ltd., Colchester, Essex (in association with Eric Bruton ASsociates Ltd), 1977. Truly a book worth getting. It's an excellent resource, and also provides information about crystal structure, cuts, and color.