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 :)
I’ve finished the UDK graveyard scene I was working on and started another :) This scene was fun to work on and it gave me a better understanding of the Unreal Engine as a whole. The most interesting part of the entire process was learning the UDK lighting system and how it handles (or doesn’t) BDRF in materials. For my next project I’m starting with a physically based shader that should make more sense coming from Maya. Putting together all the wind related meshes also taught me how far you can push cloth objects with simple skeletons and there will be more of that in my next piece.
Just before I left for Montreal I was able to snap some pics of my graveyard scene. I’ve got most of the modeling done, as well as the sky and rain systems. The Ivy on the foreground grave still needs to be skin weighted for wind movement, whereas the Ivy on the background grave is using a vertex offset to animate the ivy.
(http://www NULL.terrymatthes NULL.com/wp-content/uploads/2013/06/SceneSnippet NULL.jpg)
I’m quite happy with the look of my high detail tree, but I still have to tweak the leaf cards a little as some of them don’t line up with the branches I’ve painted on the branch cards. Speaking of vertex weights the trees also need this. I’m going to use the same material wind network the grass uses so they move together. Painting up the trunk and branches in Zbrush was fun and eventually I saved out a surface noise setting for the bark so that I could apply the same look across the entire tree without having to sculpt each notch in the bark. This setting can also be loaded up for any other trees I might create to help things look consistent from tree to tree.
(http://www NULL.terrymatthes NULL.com/wp-content/uploads/2013/06/mayaTree NULL.jpg)
(http://www NULL.terrymatthes NULL.com/wp-content/uploads/2013/06/skysetup NULL.jpg)
(http://www NULL.terrymatthes NULL.com/wp-content/uploads/2013/06/ivySetup NULL.jpg)
(http://www NULL.terrymatthes NULL.com/wp-content/uploads/2013/06/vertexIvy NULL.jpg)
(http://www NULL.terrymatthes NULL.com/wp-content/uploads/2013/06/paintover NULL.jpg)The material networks are purposefully obscured as they aren’t final and I wouldn’t want anyone to follow them as they are not yet complete. When I’m done I’ll post a better breakdown of the these. I’ve also included a quick Maya shot of the foreground tomb’s ivy and it’s vertex weighting. The base of the leaves are black to keep them from shifting and the weight falls off to red towards the edges of the leaves. You don’t have to be too meticulous with the weights as you can manipulate them in the UDK treating them just like any other RGB value.
After all is said and done I think I’m the most excited about implementing torches on the fence in the background. I apologize for the crushed levels in the video. When I get back to Winnipeg I’ll re-compress it with adjusted settings. If you visit my Youtube (http://www NULL.youtube NULL.com/user/DelightningVFX/videos) channel you’ll see the pyre tests (http://www NULL.youtube NULL.com/watch?v=w2k-J_Bhme4) I’ve made in the past and I’m going to turn these into “flipbook textures” (video game GIFs) to be used in conjunction with particles to make a really believable torch. I’ll post more towards the end of next week.
Wish me luck fellas, I’m really happy with how everything is coming together and I can’t wait to show everyone the scene when it’s complete.
(http://www NULL.terrymatthes NULL.com/wp-content/uploads/2012/11/tombstoneWIP4 NULL.jpg)Since my last update I’ve stopped working in ZBrush and started testing in the UDK. My goal for this update was to have the light maps working with a basic material in place. The first shot on the left shows the low poly tombstone with it’s UV’s layed out. These are also the same UV’s I used for the light map. If you plan your layout you can make sure that you use the same set of UV coordinates for both diffuse and light map.You still have to put the light map UVs in a second channel within Maya, but this can save you a lot of time. Making the UVs for the light map is a very similar process to making proper UVs for a normal map. You want to ensure that you have separated any faces that break out of the continuity of the surface flow. To illustrate this I have colored all of those faces blue. These faces happen to correspond to all the chips and scrapes in the model. These faces all have one thing in common. They are sharply opposing the direction of the faces around them. Faces like these have to be broken off from the model and separated into UV Islands. You’ve probably heard this term before. UV islands prevent normal map errors when baking down from your high res model to your low res mesh in programs like xNormal. A general rule of thumb is that if a face comes close to or is more than a 90 deg. angle from the regular surface flow it should be separated into it’s own island joined by any adjacent faces with the same behavior. The map pictured here is 1024 square. I should note that I left a little bit of padding around each UV group as this helps with normal and light maps.
(http://www NULL.terrymatthes NULL.com/wp-content/uploads/2012/11/tombstoneWIP2b NULL.jpg)In the picture on the right you can tell the light maps are working correctly because the shadows in the second picture are falling over the crosses as they should. If there were errors in the light maps you might get strange blotches or shadows showing up on the wrong faces. Again it’s important that we separated all those sharply angled faces so that we don’t get these errors. It’s also of note that the lower the resolution of your texture, the more padding you need to give those islands. If they are too close the shadows will start to bleed from island to island. In the UDK the entire shadow maps are being baked down to very very low resolutions to save memory. If you look at the ground shadows they are set as high as you can go with 1 pixel of screen space being dedicated to 1 pixel in the light map. You can not do this for every asset in your map or you will kill the texture memory of your video card. I only did this as a test for myself to see how far I could push the shadow correctness. Now you might look at those shadows and think they aren’t that sharp, but in a game with a textured ground and movement they are more than enough to sell the realism of the shadow.
(http://www NULL.terrymatthes NULL.com/wp-content/uploads/2012/11/tombstoneWIP3 NULL.jpg)Here we have a simple material with a diffuse, specular and normal map along with a 1 Variable Constant set to “10” being plugged into the specular power. To drop a constant down in your work area you can simply press 1, 2, or 3, on the keyboard and left click. Specular Power operates like Eccentricity on a Maya material. The higher you put the number the more “glossy” your highlight becomes. We are dealing with stone here so we’ve entered a low value of 10 as the porous nature of the stone surface would scatter a lot of the diffuse light being cast. The map we’ve used for the specular is actually a darkened version of the cavity map with some noise applied to help sell the diffuse nature of the stone surface. The cavity map works well as a specular base because it stops the cracks and depressions from casting light out into the scene and in turn sells the sunken nature of those areas. One last thing I wanted to touch on was your low poly mesh’s normals. I found that if I let the UDK set my vertex normals (which is does by default) my faces looked too sharp where the texture seams were running and I generally wasn’t happy with the result. I spent a bit of time setting all the normals in Maya and I wanted to use those instead. Luckily you can do this when importing.
(http://www NULL.terrymatthes NULL.com/wp-content/uploads/2012/11/tombstoneWIP5 NULL.jpg)When you choose to import your mesh you can select a couple options that will stop the UDK from wiping out your normal values. Under the General section and Static Mesh sections there are two options; Import Tangents and Explicit Normals. Check both of these off. If you do all of this and your still having trouble with shadows falling improperly over your object you probably haven’t turned your light map settings up high enough in your mesh’s properties. If it’s the “ground” that isn’t showing shadows correctly then the same holds true for whatever surface the shadows fall onto. Remember though that with a static mesh you want a higher number for a crisper result and with BSP geometry it’s a lower number that casts a crisper shadow.
That’s all for now :) I’ll be back with more soon and hopefully have some of the actual scene to show. If anyone has any questions email me or just ask them in the comments section within this post.
(http://www NULL.terrymatthes NULL.com/wp-content/uploads/2012/11/tombstone_wip NULL.jpg)Over the past few years I have really started to feel dependent on Maya as my 3D application of choice. It’s an amazing piece of software, but when it comes to creating game assets ZBrush eventually came impossible to ignore. This is my first attempt and producing a game asset from start to finish in ZBrush. To help me get started I sat down with a friend of mine who is a character artist by trade and spends a lot of his time in Zbrush. After learning about some really important concepts such as Poly Groups and using Zspheres for retopology I was on my way. The low poly on the left clocks in at ~1K polys which is what my target was. The original on the right was about 4 mil, but that doesn’t really matter because we are only using it for baking our texture maps. The next step for me is to UV map the low poly version and then it’s off to xNormal (http://www NULL.xnormal NULL.net/1 NULL.aspx) for transferring the details from the high to the low.
The stub mesh I started with was created in Zbrush using Shadowbox and the black and white texture below. I looked at my concept art and created a Z axis portrait and a X axis portrait of the tombstone for the Shadowbox alpha. I really like this work flow as it’s incredibly fast and can save you a lot of time when it comes to creating your base to sculpt on. The cuts in the rock surface were made with the clip curve brush and then I used the Trim Dynamic brush to flatten out the sharp edges. The rocky noise was made using Surface Noise and then repeating the process after masking off certain portions of the mesh using the Mask by Cavity function.
(http://www NULL.terrymatthes NULL.com/wp-content/uploads/2012/11/grave_D NULL.jpg) One thing I found useful was the ability to save out noise profiles for later use. I have about six tombstone to make so not having to toy with the noise curves for each one will save me a lot of time. The last step was to go in by hand and carve in individual cracks with the Dam Standard brush. This mesh is going to be used in a scene I’m creating for the UDK. I’m really excited to attack this mesh with poly paint after it has UVs as I recently watched a great video (http://www NULL.cgnuggets NULL.com/collections/frontpage/products/september-2011-video-polypainting) on the subject by Jesse Sandifer. More to come soon :)