Creating Bolt Gun with Substance & Toolbag

Introduction

Greetings! I am Carl Maddison and I will be commencing my final year at Teesside University this September 2018, studying a BA degree in Computer Games Art. I have been involved with 3D modeling for around 6 years now, initially discovering this medium on a Game Design qualification at Gateshead College. 

I have since expanded upon my skillset at Teesside University in the UK on a variety of projects, to progress my portfolio and knowledge. The end goal is to secure employment in the very competitive and diverse Games Industry. The journey so far has been brilliant!

Even though module work has finished at the university for the summer, I am always trying to further progress, so I work on personal projects and mainly centralize around the prop and environment creation. It never truly feels like work however as it is a hobby and I enjoy it.

Research

Alien Isolation is a fantastic game full of suspense and I purchased the concept art book a while back, to gain further insights into the concept and creative processes involved in the development.

I picked the concept art of an unused variant of the Bolt Gun to model and texture. This allowed me the chance to create organic orientated details such as welds, cloth and duct tape alongside hard surface elements. This for me is ideal for learning a wider range of techniques and software. It is also a good technical exercise in following a given art style, where I have a particular interest in Photorealism. 

Based on the concept art I sourced as much reference material as possible, specifically looking at the construction and materials of the individual elements that make up the Bolt Gun.

The Bolt Gun design is jerry-rigged and make shift but it still needs to reflect a level of plausibility and function, even if it not based on a real-world example. Like any project, the research, planning, and reference really help alongside any blueprints or concept art.

 If I use google image search, I always try to find higher resolution images for more clarity, using the search tools and selecting larger images sizes, assists this endeavor. Being able to examine the micro surface detail of object materials helps massively in the texturing phases. I have provided a mood board of a small selection of images out of a collection, I gathered. 

Block out

The bulk of the modeling took place in 3ds Max and in the software I make use of layers. I utilize a separate layer for my High and Low Poly models, a layer specific to references and scale where I keep reference images and an Unreal Mannequin for Scale and finally a Dump layer I keep for items I duplicate, so I have access to the originals should I need them again. My unit set up in 3ds Max is set to Centimetres (cm). 

Using the concept art and reference images I produced a block out of the weapon, it is always worthwhile looking at shapes in concept designs and art. You have access to an array of primitive shapes in 3ds Max that can be used to quickly form the basis of a model beyond cylinders and boxes. A prime example would be the capsule Primitive used to recreate the gas bottles. The block out process is important for scale and planning. 

Modeling Process

Once I am happy with the base shape and smoothing groups are established, I will duplicate the model to create the High Poly mesh. Each piece is named appropriately with either a ‘_low’ or ‘_high’ suffix. This is so Substance Painter can bake like for like parts using the mesh names. 

I favor the double turbo smooth method for the creation of my High Poly model. This helps to cut down on the use of edge loops and puts you into a situation where smoothing groups are already set up for the unwrapping process. The first turbo smooth in the modifier stack is controlled by the smoothing groups, the second helps soften the edges slightly whilst still retaining the shape. 

I reset the XForm on the Low Poly before unwrapping and with exception of cylindrical UV shells most of the model will flatten and pack into the 0-1 space, using the split by smoothing groups function introduced in 3ds Max 2017. Similar functions are available in the free TexTools plugin for any users who run earlier versions of 3ds Max.

I will then manually organize my UVs shells the best I can, utilizing the 0-1 space. I usually move all my shells off to the right-hand side and starting with the larger more prominent pieces on my mesh piece by piece. I will work from the bottom left-hand corner where I set the new pivot and select all the UV shells. This allows me to scale all the objects in unison, retaining an even and consistent texel density. As more shells are added I reduce and reorganize trying to maximize the use of texture space available.

I try to keep shells as straight as possible particularly along the edges to help prevent stepped aliasing but the natural geometry of some of the shapes in each model will not always allow this.

In this instance, the bake has been successful in correlation to the Unwrap. 

For the welds, I wanted to retain that detail in the Low Polly silhouette so the more prominent welds are modeled in. To create the High Poly welds I imported the High Poly Bolt Gun body into ZBrush, then Dynameshed the model to give even geometry across the surface and a reasonable resolution to retain details. I used the Standard, ClayBuildup and Smooth brushes to detail and build up the welds. I then masked off the welds, inverted the selection mask and deleted the rest of the model.

I then imported the High Poly welds back into 3ds Max and they sat over the High Poly body This allowed me to duplicate them and use the pro optimizer modifier to significantly reduce the poly count but retain enough geometry so the weld details could be baked down. Topogun, decimation master or the 3ds Max retopology tools can also be used, but in this instance, I received a quick and efficient result for what was required.

I created the duct tape meshes by creating a plane and subdividing it with TurboSmooth. I then used the conform brush in ribbon tools. By selected the cables and bolt gun body I was able to paint on this mesh so it conformed and adhered to geometry underneath it. This saved me having to manually edge model around each element and the shape was established ready for further detail in ZBrush. 

For the Hoses and Cables, I simply created cylinders with the required diameter and used a world path deform along a spline, that maps out the geometry’s route.  I could edit the spline with ease and in turn, the geometry would follow. This was particularly useful on the cables, finding positions I was happy with, I would be dealing with simple spline vertex points and not segmented cylinder geometry harder to work with.  

This, of course, is not the only method; the loft tool can also be used. A predetermined spline shape can be cast along a spline by selecting spline shapes and the user creates in the viewport. I have provided an overview of both methods. 

Texturing

I used substance painter for my baking and texturing needs. Baking by mesh name saves me having to explore the model to avoid baking errors and in turn, I have an array of maps available to me in the same software package. The Bolt Gun uses a single 4096 x 4096 texture, this is intended first and foremost as a portfolio piece. The texture could easily be reduced in size however for use in a game.

I initially start with a folder called Normals, these will contain layers specifically related to normal details and stamps. It is quicker for me to stamp in further normal details than it is to model geometry into the High Poly. I also have more control over the intensity of these details as they are entirely independent to what is baked down. 

I use substance Painter to add finer tertiary details to the model where possible. This is prominent in the duct tape, a procedural shape was used on the height channel and the tiling was increased to give the representation of reinforcement threads found on duct tape. This helps keep the High Poly manageable in terms of polycount.

I also make use of edge generators and smart masks initially with a warp filter, to establish some varied details but work further into the texture manually to fend off the complete procedural look. Part of this process includes the variance in colors around the welds caused by heat.

I created a simple 256 x 256 gradient in photoshop and imported it into my Substance Painter shelf. This was then used on a paint layer set to overlay to complete the effect. It hints at nuances and color variances. 

Rendering

I used Marmosets Toolbag 3 to present the Bolt Gun. For this I keep my setup very simple, mainly use 3 to 4 Omni lights and the main camera.  What I look for is light scatter and diffusion across the model, picking up variances in the roughness map. I noticed the official models of Alien Isolation were presented on a darker background (Artist: Jack Perry) so retained that for my renders. Through stages of development, I am importing textures into Toolbag 3 to examine the textures and look on the Bolt Gun model. 

I used a Metalness-roughness PBR workflow, so I disable sRGB in the options for my Normal, Meatless, AO and roughness maps. The imported roughness map is also inverted so it displays correctly. On a roughness map, white illustrates a rough surface with matte-like qualities, whereas black illustrates a very reflective surface with a lot less light diffusion across the surface.  This is reversed on gloss maps.

There is probably a multitude of ways the methods in this breakdown can be accomplished. I have just listed some of the predominant techniques I have personally used and experimented with, and hopefully, you’ve found them helpful and insightful.

Carl Maddison, Environment/Prop Artist