Black Qualls Cave: Making Vegetation in SpeedTree and Substance Tools

Philip Purol discussed his UE4 environment Black Qualls Cave: blockout and organic composition, vegetation workflow, texturing in Substance Designer and Alchemist, lighting, and more.

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My name is Philip Purol, I am 21 years old, and I’m an environment artist. When I was a kid, I was always playing games. I wanted to know how they were made and realized I wished to be part of making them. I have bounced around from wanting to be a concept artist to a character artist, finally sticking with environment art.

I studied at George Brown College and graduated with an Advanced Diploma in Game Art in Toronto, Canada. After I graduated, I got a contract job as a Gaming Artist/Designer at Gamepill for a few months. Wanting to improve my skills in vegetation, I decided to do a  mentorship at The Mentor Coalition with Billy Matjiunis.

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Black Qualls Cave: Idea and Goals

I recently finished The Last of Us Part II, and I took a lot of inspiration from the swampy sections of the game. However, I wanted to throw a twist on the cypress swamp you would normally see, so I decided to create a rich conifer swamp which is more commonly found in Canada. The idea of the project changed a few times but it always revolved around the cave. At first, it was an airplane crash and the surviving passengers went into the cave, then it was a cultist group that was holding up in the cave and the abandoned building. I finally sized down the project as I felt the scale of my ideas was too large so I went with an expedition that stopped on the plot of land to explore the mysterious Black Qualls Cave.  

My goals for the project were to improve upon three key things I felt were lacking in my portfolio: firstly, vegetation creation skills as I had only slightly dabbled in SpeedTree before, creating some more simple pieces like ferns or potted plants. Secondly, I wanted to touch upon my composition as I knew some general rules but I felt like my previous projects were missing some things such as framing. Thirdly, I wanted to improve on my presentation for the project as all my previous presentations of project breakdowns were just thrown together.


For the blockout I wanted to get the base placements of all the main aspects of the scene, like the building and entrance towards the cave, and general foliage placement. After refining the blockout for a week or so I mainly focused on getting the composition right for my hero shots. I used the trees as frames and as a way to guide the eye by angling them towards the main focus of the scene, which is the cave.

I planned the environment to have the swamp as one section of the scene to show off the vegetation I created. I wanted a contrast of broken trees and dead grass compared to the more lush overgrown section. Then there would be the building where the cave explorers set up their camp with their gear all laid out which allowed me to create additional props like floodlights and storage boxes. To add some story to the scene I hung up the cloth on the side of the building with “Those Who Enter Don’t Come Back” painted in red, making the viewer question what happened and what’s in that cave. Lastly, there is the path leading towards the cave that is emitting a mysterious light; it draws your eye towards the small hole in the rock formation.


For the vegetation, I wanted to focus on quality over quantity so I created just two species of trees: white pine and maple. I also created a round-leaved dogwood shrub for the lower ground, giving the scene some pop with its white flowers. Besides that, I made fowl manna grass with multiple height and density variation.

To add variety into the scene I created kits of each species. For example, the pine tree had two fully grown variations: two saplings, two dead variations, and then a set of fallen leaves and branches to scatter around the tree. The grass was slightly different. I created a thick cluster and a thinner one, then I had tall, medium, and small height variations. Some special clusters were created for the path to have some grass leaning into the path as well as some extra small thin sets of grass to place on the path.

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I used SpeedTree from high to low poly and used Substance Designer to put together the atlases and make slight changes. The workflow I followed was first to collect some reference from the internet, then I found the tree species in my neighborhood and collected some of my own reference. The key things I was looking to capture were the pine clusters that I would replicate in SpeedTree and the formation of the branches, as well as a whole shot of the tree.
After I collected references, I created the highpoly clusters and branches in SpeedTree and atlased them together in Substance Designer.
I was now ready to move on to creating the tree in SpeedTree. I started off by creating the trunk and the main branches, making sure I got the silhouette of the tree right first. Then I spawned the branch from the atlas with bifurcating branches using anchor points to spawn the pine clusters on the branch to give it a more volumetric feel.
The polycount was a bit on the higher side, however, I considered it as a portfolio piece and I really wanted to push the visuals. If it were for production, I would cut back to 16-18k polygons and use LODs. I kept the max draw count for trees to two draw calls, and I also turned off mipmaps in engine to achieve more crisp looking textures.  
For the grass as always, I started off by collecting reference. Once I collected enough references, I went into SpeedTree to create the high poly grass strands. It was a mix of using images I took and Substance Alchemist to extract the data from the grass blades to get the normal and other maps like albedo, roughness, and ambient occlusion. I still had to mask the opacity in Photoshop as I was not happy with Alchemist’s auto opacity masking. I also had to make the high poly of the grass strand with the seeds as I was not able to get any photos of it.
Like with the tree, I made some cluster variations, then put them together in an atlas. Then I made grass-like bundles to remove the flat grass card look, so when you look at it from different angles it hides the fact that it’s just a plane. Once I created the grass bundle, I spawned them around using the zone node, making sure the radius of the grass set was set to around 3m in radius and the max polycount being 800 polys. Having all these variants of grass allowed me to blend them nicely in Unreal, and gave a natural-looking falloff when going from tall dense grass to smaller more spread-out grass.


This was the first time I tried to integrate some photo-scanned textures into my workflow. For example, the tree bark is scanned.

First, I went out to find a pine tree I would be able to capture with my DSLR camera and a tripod.

Once I captured the tree trunk, I processed the photos through Lightroom and then imported them into Agisoft Metashape and created the high poly of the trunk. I then made a low poly cylinder and mapped it to fill out the whole UV space. I then found I had the best bakes in Substance Designer compared to other programs like Marmoset and xNormal. Once I had the bark baked in Designer, I went through some adjustments like canceling out any baked ambient occlusion in the base color and color adjustments to level out the colors, made it tile, and created a roughness map.

I mainly used Substance Alchemist to blend materials together and used the atlas scatter tool to spread around some leaves and twigs I captured. I started off with just simple dirt I made in Designer that I wanted to use for the path in the scene, and then I combined it with the rock material I made to give it some variation. After that, I used the atlas scatter layer to spread some maple leaves, dry pines, and twigs I captured to give it an extra layer of depth to the material.

Substance Alchemist is a great program that streamlines a lot of the more complex things that can be done in Designer if you're scared of all the nodes. For example, I blended a lot of my terrain materials together to get a more consistent feel to them, and I also scattered the leaves and twigs I had on a majority of them to make it feel like they all come from the terrain.

Natural Composition

A big part of the scene I wanted to work on was the natural feel of the organic growth. So, with the help of my mentor Billy, I learned about the natural placement of trees and foliage. For my scene I had the fully grown trees, then I placed saplings around them. Around the base of the trunks, I scattered twigs, leaves, and rocks that would gather up around it. I did the same with the larger rocks. The only difference was that I had a build-up of the dogwood shrubs I made around the rocks and I repeated this pattern around the whole scene.


For the lighting, I needed to keep it simple as it was an exterior scene, so I kept it just to a directional light and skylight, and I also played around with some volumetric clouds and fog. All lighting in the scene was moveable and I only used some point lights for lighting up the building as it was getting lost in the shadows and the light emitting from the cave. The lighting went through many changes and since it was dynamic I was able to make changes quickly without having to wait hours to get a bake done. I found the night lighting to be appealing as well so I pushed it further by creating a night scene with the floodlights and the glowsticks.


The biggest challenge for me during this project was being okay with having to revise the grass and other vegetation multiple times, as I had to change the grass shape of the base to taper all from one point for most of the clusters. I also did lots of color adjustments and redid the whole grass set a few times until I was happy with it. My mentor helped me whenever I had a question regarding how I should go about creating something or just overall lighting or composition. I like to think of it as an all-in-one place where I didn’t have to do a bunch of searching to find out how to make a piece of grass look good. Also, I was able to get personalized feedback constantly which can sometimes be hard to get from online communities. 

Looking back at the project I’m very happy with what I learned and I will be using it in all future scenes I create. I would love to talk about any possible career opportunities; if you would like to get in touch with me you can contact me through my email or ArtStation

Philip Purol, Environment Artist

Interview conducted by Arti Sergeev

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