Guide for creating Trim Sheets

Creating and Designing a Trim Sheet

By Jason Berry-Hemmer

Contents Title Page .................................................................................................. 1 Software ................................................................................................... 3 Planning.................................................................................................... 4 Ultimate Trim Technique ................................................................................................. 5 References....................................................................................................................... 6

Modeling .................................................................................................. 7 Sculpting................................................................................................. 11 Baking ..................................................................................................... 14 Baking issues .................................................................................................................. 16

Texturing ................................................................................................. 18 Un wrapping .......................................................................................... 19 Example of the finished Trimsheet ............................................................................... 25

Software Used The software used in this guide will be highly interchangeable and please use what you think best suited for your comfort. Some features used in this software are not always present in others but the core technical knowledge is transferable.

The software I shall be using is: PureRef - Image collage software for references Autodesk Maya (version 2022) - Basic Modelling and UV Unwrapping ZBrush (Version 2018) - Sculpting and Tiling Photoshop (Version CC 2017) - Normal issue correction

Substance 3D Painter (Version 7.2.2) - Texturing Marmoset Toolbag 3 - Final Rendering As stated earlier these are just what I prefer to use but other software include: (Blender/3DS MAX/Cinema 4D/etc) for modeling, (Blender/Mudbox) for sculpting, Photoshop/Quixel Suite/ 3D Coat/etc) for Texturing and (UE4/Keyshot/Arnold/Blender) for rendering. Many more that weren’t listed are perfectly usable

Planning your Trim Sheet First off when creating a trim sheet, you need to know what your end goal is. The beauty of trims is how versatile and efficient they are when put to good use. For my purpose was just a demonstration of the workflow so I didn’t plan exactly how each area would be used efficiently but I will offer some examples of how you could go about it.

Taking a block out or image you would like to create is a great start where you can decide upon what will and won’t be a trim.

Breaking it down in this manner lets you understand what materials you will need and how much variety of that would benefit your scene.

For example, in this scene

by Jenifer McGarry (https://www.artstation.com/jennifermcgarry)

she has broken her scene into various materials and will be focusing her trim on Bricks / Flat stone and Decorative details.

With this idea, she began to lay out exactly where each material would be and how large of a space it required, as Seen below.

Ultimate Trim Technique This technique was coined by Insomniac Games during their time making Sunset Overdrive. I highly recommend a watch of their GDC talk on this technique if you wish for further understanding of how to use Trimsheets creatively. (https://www.gdcvault.com/play/1022323/The-Ultimate-Trim-Texturing-Techniques )

The tool has been replicated by Justen Lazzaro, who provides a free download if you wish to try any of this for these programs (Blender,3DS Max, Substance Painter, and Substance Designer) Maya is not compatible, and is unlikely for the foreseeable future. ( Tool Download -https://www.artstation.com/jlazzaro)

This tool can be very useful when creating/designing a trim sheet as it offers pixel precise creation and comes with perfect 45degree normal edges.

Interchangeable settings with presets built into the tool

The output of the settings used above

References Gathering references and compiling images of how others have gone about creating their Trims Sheets can and will be a huge help. Here is where it's also good to get some stylistic images on how you want your trim to fit into your environment. For me I chose to follow a stylized art in games such as Dungeon Defenders and Orcs Must Die.

Looking at images of the high poly used to bake will also help you later down the line, as looking at the 2D image of what Trimsheets are can be quite deceiving. Knowing if they have used floating Geometry or have gone full Zbrush sculpt can give you ideas on how to move forward with your work.

Modeling Once you are ready with your plan we can move on to getting the basic shapes and set layout in your chosen software.

In Maya, I start with a plane and then divide it up into the sections using edge loop tool and multi-cut tool. Make sure once you have the final size of your plane to make another with the same dimensions, as this will be what you bake down onto later.

After this, we begin to add a bit more depth to give us an idea of how we want to liven up our Trim Sheet. I added a few insets to the decorative rows and also little extra geometry parts to break up the simpleness.

Make sure to add thickness to the parts which you have designated to become bricks for sculpting later on. The parts that tile left and right can be left without thickness to keep the correct final shape for tiling.

Next, we will be making this model ready for ZBrush import. Zbrush doesn’t play well with meshes that are not all quads, so be careful of this and go over your mesh or use a tool such as Quadrangulate. (Mesh -> Quadrangulate)

You can also double check if your mesh has any other issues by using the Cleanup tool and checking using these settings for N-gons, Mesh holes, Non-Manifold Geometry, and more.

(Mesh-> Cleanup)

We will also give out mesh a bit more geometry to help ZBrush subdivide better.

By using Insert edge loop you can create supporting edge loops to help keep the shape of the model when subdividing.

Another way can be using the tool Crease and selecting all the edges you wish to retain their shape and increase the slider to 1.

Once all ledges are supported, we can give it a little subdivide which will help us out when subdividing in Zbrush more to get clean even topology, and uniform resolution across the entire model.

It should look something along these lines just before exporting this out to ZBrush.

Just before heading into ZBrush, I would suggest making this little jig which will help us zone in on our mesh but also crucially make sure our tiling tools in Zbrush will work.

Start by creating a 4x4 grid plane over the same dimensions of your model.

You can use that plane we duplicated earlier and add edge loops to that.

Next, select the 4 Verts you see highlighted in yellow and chamfer them and slide the width till you have a result looking like the diamond pattern below.

Once you have this, delete all faces other than the 4 corner parts to be left with a mesh with 4 corner triangles.

We will be importing this as our guide frame to focus on in Zbrush.

I discovered this method from another tutorial by Anthony Vitale, Lead Environment Artist at Ready at Dawn Studios (https://www.artstation.com/artwork/VyZZR)

Sculpting After importing a crucial part if you want to make your life easier will be to set up poly groups. This is quite an easy step and will save you a lot of hassle later down the line If you have exported as one mesh this is fine and can be sorted without reexporting everything.

Pressing (Shift+F) will toggle poly groups to visible.

On the right side of your screen, scroll down until you see the poly group tab. And hit Auto Groups

Now it should look all multi-coloured and now if you head to the subtool tab, you can split by group which will break all this down into manageable subtools. Subtool visibility and usability can be turned on and off making sculpting specific parts more manageable.

On each subtool you will want to now subdivide until you are happy with the working resolution or the amount your pc can handle due to RAM limitation. I would recommend sticking under 10mill give or take.

The next crucial step involves the frame we made earlier. Import the model as a new subtool and it should line up over the sculpt.

This next tool is very helpful for making tiling materials as it allows you to draw on one edge and it will wrap to the other side making it seamless. Head to Brush->Curve -> WrapMod and set it to 1. You may make it higher but it will tile more than once.

Be warned this will have to be done on every brush you use so maybe don't switch too often.

Now you can focus back onto the tool by hitting the F key and you will be in perfect view, this will also help with the warp mode.

Now you can begin sculpting. For mine, all I did was make it more stylized and added edge wear to the bricks.

Be careful not to add too much detail and noisy damage. Since this material will tile it will become noticeable fast.

Other than that I added an alpha stamp of a Nordic pattern to give the trim a bit more dynamic usage.

The last step in Zbrush is to Decimate your mesh as when exporting this file would be huge if not for this step.

Locate the ZPlugin a the top and find the decimation tab.

Pre-Process all of the subtools first, then once this is done you can decide how much you want to decimate the mesh and hit Decimate all. Be sure the save before decimating as you won't be able to undo it if you save and close the file after.

My model went from 7million active poly’s to around 400k. The file size for this will be much smaller and not break your baking software.

Baking Importing the decimated mesh Back into Maya as we need to duplicate the high poly on some parts to help with baking.

As you can see, I have duplicated the highpoly on both sides of the original square, and then removed the unnecessary geometry.

This will help give us cleaner bakes and make sure things tile better.

Underneath this, we will also duplicate the original plane we kept to each side. UVs aren’t an issue here as unless the shape has been modified the Uvs should be a full square in the 0-1 space, like this.

Baking can be done in multiple software but for mine, I will be doing it in Substance Painter as I will be using this to texture as well.

Project settings can be based on what you need but for me, I just went with the standard PBR template at 2k texture resolution, this can be changed at any point in Substance painter.

Under Texter Set setting on the right, you will find Bake Mesh Maps which will give you a popup like the image on the right and select the high poly mesh Adjust these to your preferences but make sure to play around with the Max Frontal and Real distances. This is your cage for the mesh and since you have a plane the frontal can be quite far off the plane to capture all the details in the bake.

Hit the bake button and then start looking for any information loss or bake errors on your maps

Baking issues Baking issues can and most likely will occur as even the slightest mistake like sculpting too far or wrong bake settings will affect it somehow. For this process, I ended up with such issues which were invisible at the time of sculpting but when baking and thanks to the 3 plane set up I was able to see and fix them.

The issue was that on the normal, where the edges tilled had some errors due to over sculpting inwards.

By taking these into photoshop and having it tile 3 times horizontally, you can use the tool Spot Healing Brush, and drawing over it will fix the issue 95% of the time. By going over it little by little you are just changing the normal map to match the surroundings and hopefully restore a perfect tile.

Close enough fix for what I need it for.

When this method fails the last resort can be to paint the normal back by hand using a normal map colour wheel and by using the colours which conform to the direction light should bounce off it in the right spots with a paint over.

Texturing This part is where you don’t really need a guide and do what artists do and create. Use whichever software you wish and turn your high poly bakes into a cool-looking texture and either try and match a style or go for something new entirely.

Un wrapping The TrimSheet is now done, awesome!

We now have to understand the basic ways to use it and we are set to create countless designs on meshes from it.

First, let's start by setting up the material in Maya to get a better look at what's going on.

Right click the model you wish to apply the material to and hit assign a new material.

Next, click the box to the right of colour and select the file box.

Click the folder button next to the Image source and locate the base colour or normal map of your trim, personal preference but I prefer the base colour. Then lastly just hit the little checker ball button on the bar above the viewport and your model should have the texture applied to it.

Let's get acquainted with Maya’s UV tool set to help out.

For the most part, we will be using a method I like to use which can UV unwrap near any shape and still give us our straight UV shells needed to make this work to the best of its ability.

An arch can be quite tricky to get into a straight UV island and so I will use this as the bases to show off this method

These are from an automatic unwrap. Good enough for unique unwrap but for Trim Sheet the arch itself is terrible.

First, we select all faces we want to unwrap then in the UV editor, we got to modify->unitize. What this does is make every single one of the faces the entirety of UV 0-1.

Next, select the edges you do not want sewen together as it is more than likely you will have less of them than those you wish to combine, select-> inverse and now you can Move and Sew.

Since everything had the texel density of the entire 0-1 grid, it will become a huge long straight rectangle. We then want to unfold it on only one of the axis, for this instance, it was the V. You will be able to tell if it is the wrong axis if the UV shell doesn’t stay straight.

Re-size this down the 0-1 space and rotate appropriately with tools shown in the quick run down.

Finally, place the UV shell where you wish and you can scale it as much or little as you like. Trim sheets have the great benefit of not having to stay confined to one UV grid.

Final results on a simple model

UVs of this doorway model

Just as the last warning be careful on scaling things too much or too little as while it is possible, some UV islands will have seriously high texel density compared to other parts and will be noticeable even at a distance. It is best to maintain a balance of scale.

There are ways to future proof this by using trim sheets with the same area but made bigger or smaller and example is from Sunset overdrive

But of course, you can get it perfect and some distortion or miss match of density is bound to happen. As showcased in mine, it's about the same but some parts are denser than others.

Example of the finished Trimsheet

An interesting thing is that without changing a single part of the UV map and just scaling up the tile amount, you can get interesting and different looks with minimal effort.

Original

Tiled 3x

Tiled 2x

Tiled 4x