Terry Matthes

[R&D] nHair Chain Strand Rig Part 1 of 2

Rigging… It’s not my favorite aspect of 3D, but that’s probably because It’s also my least practiced. What better way to learn though than to jump right into nHair and IK Splines, right :D ? My end goal with this rig is to have several strands of chain that are strewn across a mirror ball attached at several points, think of garland on a Christmas tree if you need a visual. As always to start I researched how this could be accomplished in Maya. Every tutorial I read/watched mentioned IK splines and Maya’s hair system.

It took me the entire morning, but I was eventually able to produce a chain strand constrained on a single end. The biggest problem I ran into was constraining the far end of the chain to an object. Literally all the tutorials out there are using the old Maya hair System. With the copy of Maya I currently have (2014) you are forced into using Maya’s “nHair” system and the “n” stands for “Nucleus”. Nucleus if you’ve never heard of it is Maya’s new dynamic simulation system that unifies all your dynamic elements so they can operate in conjunction with each other. It’s Very similar to how Side Effect Software’s program Houdini works. So great, “yay”, everything works together, but all the constraints mentioned in the tutorials I watched are based on the old hair system and they do not work with nucleus hair. So this is as far as I have gotten today, and It will probably take another half day to find the proper type of constraint that acts in the same way a “stick” constraint does with legacy hair.

There are plenty of scripts out there that will do this task for you, but I try to avoid scripts when learning. I that find that; (A) it’s essentially letting someone else do the work for you which means you didn’t actually learn anything and (B) depending on how the script works, it could have unintended consequences immediately or down the road. For those of you who have never created anything like this before and are looking for answers here are the steps I used to create the rig and as always don’t be afraid to ask questions :)

Model a chain link and then duplicate it over and over to create whatever length of strand you need.
Use the joint tool to create a joint chain all the way down your strand putting a joint between each place where the pieces of chain meet up.
One by one starting with the top chain link and the top joint use the rigid bind tool to bind each link to its corresponding joint. In the rigid bind options make sure you have the “Bind to: Selected joints” option activated.
Draw an EP curve down the length of the chain adding a point over each of the joints you previously created. Press to “P” key to activate pivot snapping and your points will automatically center on the joints. Rename this curve something like “epc_original”.
Make your curve a dynamic nHair curve through the nDynamics > nHair menu. You need to first make sure that the only option in the “Make Selected Curves Dynamic” option box that is selected is “Attach curves to selected surface”. This will now create a hair system and follicle system in your outliner.
The last step is creating the IK spline and this is where most people make a mistake because they select the wrong curve. In the Animation > Skeleton menu select the option box for the “IK Spline Handle Tool”. Make sure the only option selected is “Root on curve”. With the tool active click in this order… the first joint of your joint chain then the last joint on your joint chain and now open your outliner and hold down ctrl(PC) or cmnd(Mac) and select the curve under the “hairSystem1OutputCurves” node. An IK node should now appear in your outliner.
Lastly select the original curve and parent it to whatever piece of geometry you’d like to constrain the top of the chain to. Now if you use the interactive playback feature and drag that geometry around your chain will follow.

As soon as I figure out how to constrain the other end of the chain with nHair I’ll post an update, and if anyone figures it out before I do then please let me know. Bye for now :)

UPDATE!

Part 2 : The rig gets completed with moveable anchors at both ends. (http://www NULL.terrymatthes NULL.com/maya/animation/nhair-chain-strand-rig-part-2-of-2/)

[R&D] Feeling Winded…

After finishing the fire effect for my project it’s time to move onto the wind portion. To create a tornado the first thing I did was jump into Maya and start setting up emitters in a fluid container. Good lord was that a bad idea. The particle motion to create a tornado consists of a lot more than fire and it’s very hard to control a fluid container with multiple emitters when you don’t know exactly what look you’re going for. After a mornings worth of work I wasn’t where I wanted to be because I still couldn’t identify how my emitters were moving the fluid around. To see anything in real time on my Mac Mini the container settings have to be low. So low that it’s not indicative of the final motion. Not even close. I started to search on the internet and found a good thread on CG Society (http://forums NULL.cgsociety NULL.org/showthread NULL.php?t=1040698) where an artist responsible for clouds and tornadoes in Resistance 3 had made a few posts. I was pointed towards using a regular particle setup to nail the look and then control the fluid container with those particles. Brilliant!

In the afternoon I created my particle tornado. It consists of 5 emitters. One large torus emitter to create the center of the tornado and 4 smaller cylindrical volume emitters placed around the base to simulate the upward streams of air you get that contribute to the storm. Beyond the 5 emitters there are a total of 4 force fields that create the motion. The first force field is a uniform field that pushes the particles straight up. This is similar if not the same as a gravity field with a +Y force. The second field is a cylindrical vortex volume. This volume spins the particles while keeping them in a cohesive shaft. The third field is a cylindrical axis volume field. This is what makes the tornado spread outward from top to bottom. I’ve set it’s “around axis” attribute to X0 Y1 Z0. This tells the particles to spin around the Y axis. The attenuation value on this field is set higher so that the particles don’t instantly push out to the edge of the volume.

Attenuation acts like an ease in and out of the volume. If you set the attenuation value to zero on any field the particles will take on the motion of the volume as soon as they enter it’s space and this can create abrupt changes in direction. The final volume is a spherical volume axis field that has been squashed and placed atop the cone to push the particles outward. I’m using the “away from axis” set to X0 Y1 Z0 to achieve this.

For the first hour or so I really struggled to get the particles to follow a nice swirling motion and then I discovered my mistake. I have to set the particle’s (not the emitter’s) “conserve” value to 0. This stopped the particles from inheriting any initial motion and gave the force fields full control. If you don’t do this it’s an uphill battle to control their initial momentum. Now that I have my particle system down the next step is to create a fluid container that these emitters will be parented to. I’ve been told that since Maya 2011 particles and nParticles have been able to emit voxel data into a fluid container. Well see how well that goes…

(http://www NULL.terrymatthes NULL.com/wp-content/uploads/2013/12/terryTornado NULL.jpg)

UPDATE

I got my particles emitting voxel data to the fluid container in Maya. I forgot to turn buoyancy off of the fluid container so the particles keep going up past the top of the funnel, but I’ll fix that on my next go. The fluid container is using the density information to shade the particles.

[R&D] Fire Starter

I’ve started a new project involving Maya and Zbrush and a big part of it is going to use simulation data from Maya. There are three parts, smoke, water, and fire. I haven’t created a fluid effects fire in a while so I thought I would spend the morning working out some flames to get back into the swing of things. This fire was made from a 3D fluid container using a volume based emitter in Maya 2013. After I had parameters I was happy with I baked out the simulation into a cache file. This makes the rendering way faster as you’re not trying to simulate and render each frame at the same time. It also lets you store that data and scrub through your simulation.

I’m working of a Mac Mini right now which is a little weak in the processing department, but hey at least I have something to work with. Come Christmas I will be visiting Winnipeg so that I can get my computer along with the rest of my apartment and move it here to Montreal.

The end result for the project will be a lot more stylized, especially when it comes to colour. I find its always best to match the physical phenomenon as best you can before you start to push the style. The YouTube compression beats up the softness and sharp contrast of the flames, but it’s just a test so I didn’t want to have to sit and wait for a 180 frames and 1080p. This will do as a start for the next step of the project which will be shaping and re shading the fire. As always if you have any questions don’t be afraid to ask. I don’t bite, I promise :)

UPDATE

I squeezed in some more time this evening to iterate further on the flames, playing with the colour settings and getting them to spin the way I wanted using Maya’s force fields in the fluid container. This particular test makes the flames too skinny and high, but I feel I’ve nailed the mechanic down to make them spin.

MIGS 2013 Adventures

I decided to attend the Montreal International Game Summit and wow what a blast. I didnt meet anyone else from Winnipeg there, but that’s OK becuase I meet some really nice people who made me feel at home instantly. There were a lot of nice recruiters there and I would reccommend anyone with a portfolio ready to go attend. They gave me some great feed back and never made me feel like I was wasting my time even after standing in line for an hour to tak to some of them.

After the end of the first day I was standing alone in the lobby wondering how to kill time until the after party. To my left a man with a pretty sweet beard was handing out furry viking hats. I wanted one, but he gave away the last one in his hand before I could pipe up. I pretended to toil away on my smart phone not wanting to show the hurt I was masking inside for missing out. Somehow though he could sense my want. He called me out for pretending to look busy and said “Don’t you worry. We have more hats.” His kind smile melted my faux shell of pretentiousness. “Yes please” I said, and from that moment on they had a lonley Winnipeg puppy who was determined to make them his friends.

All of the team members from Big Viking were beyond nice and I wanted to say thank you for making me feel like one of the guys that weekend. We had a lot of fun at the MIGS party and they helped me meet some really great people from all over Montreal’s game industry. Go check them out at http://www.bigvikinggames.com/ (http://www NULL.bigvikinggames NULL.com/) and know they are doing their best to bring you really fun games.

(http://www NULL.terrymatthes NULL.com/wp-content/uploads/2013/11/cupcake NULL.jpg)

[Game] Snowy Turn Table Final

Another day and another piece done :) I had a great time putting together this snowy turn table and trying out all sorts of different methods in ZBrush for creating snowy surfaces. For some extra fun I even threw in some “Matinee” animations using Unreal’s animation system.

The snow covered assets in the scene use what is basically a layered material to map the snow, ice, and base materials over their surface. This is done through using the “Lerp” node in the material editor. If you’ve ever tried to create a layered material in Mental Ray you will appreciate what the lerp node does. Using an 8 bit (gray scale) map the Lerp node transitions values. Think of it like a mask. You can use a bunch of these Lerp nodes in a single material to create a layered shader. There are other ways of getting more than one material on an asset in the UDK though.

When exporting your assets as “FBX” files in Maya you can assign up to six (as of Unreal Engine 3.0) different materials per mesh. This is done through simply creating up to six different Lambert materials and applying them on a per face basis. This is a very convenient way to assign materials to your meshes, but it does have it’s downsides. Firstly, you are adding extra draw calls for each new material you assign your asset. This differs from using the Lerp node because with Lerp method all your different surface types are constructed within a single Unreal material and consequentially, a single draw call. Secondly, the borders of your materials must lye along the edges of their assigned faces. This can end up giving you abrupt transitions that won’t look as smooth as painting a mask for a Lerp node. Going forward I would like to expand on what I’ve done in Matinee and produce an animated character with some dynamically driven accessories.

Oh yeah, I almost forgot to mention that I’m moving to Montreal Canada. I’ll be heading out November 5th and my first stop will be their Independent Game Developers Association. I’m super excited to meet fellow developers and check out all the wonderful studios in Montreal.

[Game] Snowy Turn Table WIP 2

Here is an update on my snowy turn table I’ve been putting togeather. I’ve added some animated lighting and given most of the meshes another iteration of detailing and fixes. The next thing I have to do is finish the snowy bushes and make the ice on all the meshes more obvious. As a final touch I might at a sun and a moon togeather with the proper positioning of those respective lights. So have a look :)

[Game] Snowy Turn Table WIP 1

Hi guys and girls I just thought I would post a quick update on a collection of assets I’m creating for an upcoming iOS title. It’s a snowy scene and there are more meshes to come. I haven’t worked on cube map reflections yet, but I will soon. All meshes are built in Maya and ZBrush :)

[R&D] CGFX Shaders: Cubemaps

After my work establishing a Phong model shader I wanted to incorporate cubemaps. Everything went fairly well. The next step is to combine this shader with my normal map shader.

If all goes well I can get that done tonight. I’m having a lot of fun with shader authoring. It’s a nice blend of computer science and art that I’m really enjoying. My end goal for learning CGFX is to be able to produce a small scene in the Unreal Engine where I’ve written all the shaders. Wish me Luck!

My First CGFX Shader

I’ve put if off for a while, but today I decided to jump into writing shaders. It took a while and a lot of wikipedia searches, but I finished tonight after having started this morning.

It’s a Phong shader based on a Lambert model. It has an added Fresnel highlight as well as controls for the glossiness strength and size. For textures it accepts Diffuse, Normal and Specular.

The next part I’d like to add is reflections and more specifically; cubemap reflections. I’m moving to Montreal soon and I think my best chance for work is to apply as a material artist.

I’m hoping my film work combined with my portfolio website and a new library of free to download materials will help me land a job. The maps it’s using right now are from an old ZBrush project, but they are good enough for proof of concept. More to come soon :)

(http://www NULL.terrymatthes NULL.com/wp-content/uploads/2013/09/test_shader2 NULL.jpg)

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