Mar26
2012

By: admin                Categories: 3D Animation

This is video 6 of 10 from Andrew Gahan’s Maya in Minutes video series. In this lesson, Andrew reviews how to create vegetation in the 3D software Maya. Download all files used in this tutorial. For more info on the full 10 part series for Maya and 3ds Max, visit the links below.

Maya in Minutes is a series of video tutorials for Maya offering top quality, easily-digestible shots of Maya. The videos are designed to help trainees improve speed, workflow, and build good working practices. All videos offer help in bite-sized modules, so busy professionals can learn effective techniques fast – without having to sit through hours of filler, or wade through loads of documentation. All tutorials include a PDF summary of the lesson and Maya project files, so the artist can master techniques quickly.

Maya in Minutes: http://www.focalpress.com/books/animation_and_3d/maya_in_minutes.aspx?terms=m…

3ds Max in Minutes: http://www.focalpress.com/books/animation_and_3d/3ds_max_in_minutes.aspx?term…

Video Tutorial:

Tutorial Summary:
In this video we’ll look at common techniques used in the games industry to create vegetation.First we will look at the basic techniques of creating grass to be used in-game. Because most game engines can’t afford to model every leaf or blade of grass, the solution we will cover is how to apply texture maps with alpha maps or alpha channels to simpler geometry.

These alpha maps are black-and-white or grayscale images which, when used with a diffuse texture, show any elements in white as being opaque and black areas as being transparent. All gray values will create relevant levels of transparency. For example, 50% gray is taken as 50% transparent.

Figure 1

We will first take a look at creating some grass with this technique. We willexplore the process of how a diffuse or color map can be created from photos, scans of grass, or, in the case of the tutorial, using a render from 3-D geometry, which also gives us an accurate alpha channel.

Figure 2

If you prefer to use a photo to create the texture, we also cover the process of doing that.

We will take you through the process of painting the white area of the alpha channel by painting it manually. We will use the various lasso, magic wand, and other selection tools to select the areas and then paint them.

Figure 3

With the grass modeling techniques covered, we will progress to building more complex bushes. We will take you through the texture creation process once again and then move swiftly on to how to deconstruct the models before you start modeling to help you to create great-looking assets in the shortest time possible.

Figure 5

We will investigate how each plant grows and how the weight of the leaves cause the stems to start bending as they grow away from the center. In the sketch of the larger plant you’ll notice how the stems grow upward and then fall away from the center, back toward the ground, with the stems closest to the ground being more horizontal and the ones higher being more vertical.

We’ll start with the process of creating the small plant first, and step be step we will build up the various types of leaf construction we can use, as well as modeling and mapping the stems. We will discuss various optimization techniques to reduce the amount of alpha to be drawn, which is very important for a lot of current generation game engines.

We will then take a look at modeling the second plant and how to introduce variety in the leaves as well as complexity in the model without adding too many polygons to the model, all using the same techniques we’ve been using throughout the tutorial.

Figure 6

Finally, we will investigate how to build up a scene from the assets we’ve created. We will discuss which assets to place where and why and how to consider composition and placement from the player or viewer point of view.

Figure 7

Andrew Gahan is a leading industry expert in next generation consoles and digital gaming. His roles have included Senior Artist, Lead Artist, Art Manager, Art Director, Art Outsource Manager, and Producer. Andrew is an expert in all gaming tools for commercial game development, including: 3ds Max, Maya, Photoshop, XSI, Gen Head, Z Brush, Mud Box, and Poly-boost (as well as other 3ds max plug-ins). During this time Andrew has worked on 14 standalone published games as well as sequential spin-off products; as well as developing a number of military training systems for the Warrior – Armoured Fighting Vehicle, Harrier and Tornado aircraft.

In the last decade Andrew has been involved in recruitment and development of artists, including theoretical and practical training. Andrew has been a freelance consultant helping companies to develop and improve tools and applications that are used by artists in the digital gaming industry. Andrew is currently a visiting speaker and advisor at Liverpool John Moore University for the MA digital games course; and is an external advisor at the University of Bolton, supporting the development of their forthcoming 3D related courses.

Andrew has judged the Independent Games Festival for the past 2 years. He has been a visiting speaker at Liverpool John Moore University since 2005, and will also be a speaker at the University of Bolton for the forthcoming 3D Games Modeling course. Andrew Gahan has given numerous media interviews, of which a recent selection is given below: 15 December 2007. Interview with Gamasutra magazine Media consumption: MotorStorm’s Andy Gahan. Television interview for 1-up.com with Pete Smith (Executive External Producer, SCEE (Sony)) in San Francisco, during GDC (Game Developer Conference) in the Sony Store for the launch of MotorStorm. Television interview for GamerTV with Pete Smith (Executive External Producer, SCEE (Sony)) in San Francisco, during GDC (Game Developer Conference)

1 Comment

Mar22
2012

By: admin                Categories: General

This post is an excerpt from Getting Started in 3D with Maya by Adam Watkins.

In the book – Getting Started in 3D with Maya – I continually laud the great online resource cgtextures.com. In a pinch it’s a great place to go to grab textures to place in your scene. Generally though, textures that are easily available online are great because they are quickly available online – and also not great because they are quickly available online. It means that not only you, but every other 3D artist with an Internet connection can grab and use these texture resources. I’ve personally seen multiple demo-reels where I’ve recognized a texture from cgtextures on a wall.

In some of our tutorials we’ve looked at one way to mitigate this problem through heavy manipulation and layering of texture assets. Using multiple layers with various Blending Modes can quickly customize a texture into a look that is unique to your project. However, of further customization is the ability to use your own photography assets to be the basis of the textures.
This will ensure a completely unique look; and since you took the photos, this always ensures you have the rights to the texture files.

This does require a little bit of extra work – but the original results are generally worth it. There are a few problems that emerge from your own photographs (which, by the way, can be a problem with some online resources too). The biggest problem is the problem of seams.

FIG B-1-Raw image of a stucco wall

Figure B.1 shows a photo of a chunk of a wall that I need to extract a stucco texture off of. The selected area is the chunk of that texture I copied and pasted into a new file.

The problem is that this chunk of the wall, when applied to geometry, ends up looking like Figure B.2.

FIG B-2-Applied texture - see-the-seams?

Suddenly, our stucco looks more like bricks. The problem is that when the texture repeats, we can see the seams of where each tile of the texture stops and ends. Part of this has to do with color, and part of it has to do with the breakdown of texture.

In this appendix’s tutorial we will look at removing seams from source photography. To yield a texture that tiles well across a form. But before that, let’s look briefly at a few tips on taking your own photography for use in textures.

Texture Photography Tips
1. Take the photo as straight on to the surface as possible. The lens of the camera and the surface of interest should be parallel. Getting a flat image will save loads of time and avoid all sorts of muddying of the image from over adjustment in Photoshop.

2. Don’t use a flash. Ever. Flashes create strange hotspots across the surface that are very difficult to work out.

3. Either take the photograph in the shade, or with the sun straight onto the surface. The key idea here is to avoid cast shadows from raised parts of the texture onto the surface itself. We want to make sure that a stucco wall isn’t locked into looking like the sun is at 3:00 PM in the afternoon (we’ll want to define that in our scene).

4. If available, use a telephoto lens and be as far from the surface as possible. Wide angle lenses will provide fish-eyed photographs where parallel lines (like mortar between bricks) are suddenly not parallel. A telephoto lens tends to collapse perspective and will keep your texture as flat as needed.

5. Take the photos to cover a big chunk of texture, but make sure you are capturing at a high resolution. A big 8000×8000 pixel image that covers a whole wall (that you’ll extract a small 512×512 image from) provides many more options than a tightly shot 512×512 one. In the end you’ll have the same sized texture, but the flexibility to pick the part of the texture that works best.

So, assuming that you have some good photography, or even mediocre images (my shot for this tutorial is included in the support files on the supporting website: www.GettingStartedin3D.com), we can start working through how to work the seams out.

Tips and Tricks
Try to avoid picking a chunk of texture that may include a very noticeable element that would stick out if repeated. For instance, don’t select a chunk that includes a bug on the wall, as that bug regularly repeated will certainly destroy the look of the material later. Similarly, look for a chunk that is as evenly lit as possible.

Tutorial B Creating Seamless Textures

Step 1: Open the original photograph (you can use mine or your own), and using the Rectangular Marquee Tool, select a chunk of texture that might work well for the texture base (Figure B.1).

Step 2: Copy and paste this selection into a new file. Save it as ColorResource.jpg (the file type here doesn’t really matter).

Step 3: Create another new file and paste the image into this one again. Save this as Stucco_Color.jpg (Figure B.3).

FIG B-3-Copied and pasted texture chunk

Why?
In a minute we are going to be stripping all the color from our Stucco_Color.jpg image. Seems strange now, but what this will do is set the stage to allow us to unify the color across the surface.

Step 4: Work in Stucco_Color.jpg and select Filter>Other>Offset. Change the Horizontal and Vertical sliders to values that allow you to see the seams somewhere in the middle of the image (Figure B.4). Hit OK.

FIG B4-Using the Offset Filter to bring the seams into the middle of the image


Why?
The Offset Filter is of incredible use in texture modification and creation. What it does is offset all the pixels in one direction and then wraps those pixels that it pushes off the image around so that they come in on the other side of the image. What this means is that the right edge of the image matches perfectly the left (when using the Horizontal slider) and that the top and bottom edges match (when using the Vertical slider). It means that the seams are in the middle of the image – right where we can see them, and work with them.

In this case, a few things become instantly clear. First, the color of that stucco isn’t the same as it moves across the surface. Secondly, the texture has a crisp line break where one copy stops and the next begins. Here’s where our work begins.

Step 5: Remove the color by selecting Image>Adjustments>Desaturate (Figure B.5).

FIG B5-Grayscale results of Desaturate


Why?

Notice that as soon as this is done, some of the seams become much less apparent – in this case the vertical seam practically vanishes. Getting a constant color balance across the image is a huge part of eliminating visible tiles. Not to worry however, we’ll get the color back into this in coming steps.

Step 6: Use the High Pass Filter to further unify the surface. To get to the High Pass Filter, go to Filter>Other>High Pass. Tweak Radius slider so that you are left with a further flattened image (Figure B.6).

FIG B6-Using the High Pass Filter to further flatten the image

Step 7: Use the Clone Stamp Tool to work out the still visible seams. To use the Clone Stamp Tool, Alt (or Option)-click on a spot to define a source. Then release the Alt/Option key, and where you then click and drag will clone the part of the image you defined the source as (Figure B.7).

FIG B7-Working out the remaining seam with the Clone Stamp Tool

Why?
The Clone Stamp Tool can be tremendously useful, but it’s usefulness is very situational. Sometimes, like for this stucco, a wide brush with a soft edge (defined up at the top of the Photoshop interface), provides a great way to work out the seam. But in other situations – say a collection of pebbles or bricks, using a much harder edged brush will allow you to work the seams out by cloning the exact edges of stones or bricks into place. Similarly, using a low Flow setting for the tool can sometimes allow for a very subtle layering of cloned pixels; but at other times it can just create a muddied mess across the seam that doesn’t work at all. It sometimes takes a bit of experimentation in each situation to find what works best with the asset at hand.

Step 8: Reintroduce color to the texture. To do this, first make sure that both Stucco_Color.jpg (which you’re working on) and ColorResource.jpg are both open in Photoshop. Then, select Image>Adjustments>Match Color. In the Match Color dialog box go down to the Source section and choose ColorResource.jpg. Click OK (Figure B.8).

FIG B8-Using the Match Color to reintroduce color to the stucco

Why?
What’s happening here is Photoshop is looking at the colors from our original ColorResource image and applying it to the gray-scaled version we have been working with. Photoshop looks at the luminance value of the pixels to try and match up what colors should be where – and it usually does quite a good job.

Step 9: Adjust Levels/Color saturation to taste (Figure B.9). I like using the Image>Adjustments>Curves mechanism.

FIG B9-Results of adjusting Color Balance and Levels

Why?
Through the course of desaturating the image and then using the High Pass Filter, sometimes the image can end up a little dark and lose a lot of its contrast. After you’ve got a seamless image, taking some time to adjust the results can get you back to the initial look of the original photography.

Step 10: Save. Test (Figure B.10).

FIG B10-Applied seamless version

Conclusion
Seamless textures are important; and with the steps listed above are not too difficult to create. Keep in mind that much of the efficacy of this technique relies on the quality of the source photography. If it just isn’t working, go take the photo again to get the raw stuff you need.

At the end, there’s little excuse for not getting any surface to be just right. All you need to do is find its real world equivalency, and the texture can be reworked into a good seamless repeating texture to make your work unique.

Getting Started in 3D with Maya is available at Amazon and BN.com and wherever else fine books can be found.

Adam Watkins is Associate Professor, 3D Animation, School of Interactive Media & Design at the University of the Incarnate Word. He is currently on a research sabbatical at the Los Alamos National Laboratory in New Mexico, where he is part of the VISIBLE effort creating virtual simulation games for use in non-proliferation exercises. Watkins has headed the 3D Animation program for over ten years and is the author of several books and over 100 articles on 3D Animation. His students are the winners of multiple national and international animation awards and festivals.
No Comments

Mar22
2012

By: Cedric                Categories: AnimationBooksGeneral

I was thrilled to find a copy of Action Analysis for Animators on my desk – fresh off the presses. Due out in April, Chris Webster examines the fundamentals and subtleties of action analysis and applies it to animation. In celebration, we decided to post an excerpt from Action Analysis for Animators to give you a peek at whats to come. This excerpt explores analysis of pushing and pulling in animation.

Action Analysis for Animators desk copy

Pushing

As with many actions, the level of force required to complete an action, such as moving an object, determines the nature of the action. Generally speaking, the most efficient method using the minimum of effort applies for all actions.

Pushing a button may require only a very small movement that extends no further than the fingertip. A stronger push may involve the movement of the entire arm, incorporating movement at the wrist, elbow, and shoulder. Pushing an object that offers greater resistance may require the use of the entire body in a way that employs the weight of the body to apply additional force beyond that applied by the effort of the muscles. During this type of push the angle of the body may be positioned not directly above the feet, as in a normal standing or walking gait, but extended beyond the position of the feet in the direction of the object. In this fashion the weight of the body is used to provide the additional force.

Pushing a static object requires a degree of force to overcome the inertia made up of a combination of the object’s mass and any friction between the object and the points of contact with any surface on which it sits or has contact. The more resistance there is at this point, the greater the force required to move the object. There will be a greater level of potential friction between an object sitting on a heavily textured or soft surface than one sitting on a hard, flat, and slippery surface such as ice. Attempting to push an object with a flat bottom may require more effort than pushing a heavier object that either has less friction or is designed to aid smoother movement, such as objects that possess runners, blades, or wheels.

FIG 5.70 Various poses of a figure pushing a static object.

Pushing a wheeled object such as a wheelbarrow requires far less force to overcome inertia and enables far greater loads to be shifted for the same degree of force. The wheel provides a lower level of friction between the load object and the surface through the rolling action as opposed to a sliding action of two flat surfaces. Once inertia has been overcome, forward movement may be maintained by the steady application of force, created as continuous pressure is applied—in this instance, as the figure walks forward. If the weight is very heavy, the pushing figure will tilt forward from the upright position to gain greater purchase with the feet

a: Man pushing a load on a hand trolley.

b: Woman pushing wheelchair on flat even ground.

c: Man walking backwards while steadying a wheelchair as it moves down a slope.

d. A man pushing a wheelbarrow with heavy load.

Pulling

Many of the same issues that are evident in a pushing action may also be seen in a pulling action: the need to overcome the inertia of an object and the amount of friction between the object and surfaces and the use of body weight to increase force. Pulling may be undertaken simply by the movement of the fingers. Greater forces may be exerted simply using the hand with a movement at the wrist. Pulling an object by the use of rope, if not too heavy, may be undertaken by a hand-over-hand action that can only entail the use of the arms. This action entails each arm working in turn to pull on the rope toward the body, one arm pulling on the rope while at the same time the second arm extends forward to gain a grip on the rope in preparation for a subsequent pulling action.

Heavy objects may be moved through a pulling action using the body weight as part of the pull. This can be achieved by the figure facing the object while holding the rope and extending the body away from the object, thereby applying a force using the weight of the body.

The drawings indicate how the weight of the figure is extended beyond the center of gravity using the weight being pulled as a counterbalance.

Alternatively, the body may be turned away from the object with the rope placed over the shoulder and the hands gripping the rope firmly placed close to the body before the figure commences to walk forward. This may entail the body being angled in a position forward of the feet. In this way greater purchase may be gained by the feet on the floor, thereby exerting greater force.

Pulling on a rope over the shoulder.
Action Analysis for Animators
will be available at Amazon and BN.com and wherever else fine books can be found on April 16, 2012.

Chris Webster is an animator who has worked for twenty years in the industry and has extensive experience as an educator teaching across a broad range of levels from schools, higher education and professional training programs and within the studio environment. He is currently Head of Animation at the Bristol School of Animation and the University of the West of England.
1 Comment

Mar20
2012

By: admin                Categories: GamesGeneral

Focal Press is excited to announce a new addition to our collection of blogs and mastering sites – launch details coming soon.  We are currently seeking game design/development, and web design/development  professionals who are interested in writing for the Focal Press community.

Join our team of award winning authors, professors, and professionals if you have experience in the game and web design industry and want to shape a community that will train designers and developers, provide thought provoking commentary on the industry, and report keen insights on the latest research trends and emerging technologies.

We are offering a cash stipend for articles 1,000 words or less in the fields of game design/development and web design/development.  If you are interested please contact Cedric Sinclair to discuss your experience and proposed articles.  Please visit MasteringPhoto and MasteringFilm to see the kind of impact we will make in the Game and Web Design industries.

1 Comment