Creating a Cthulhu-Themed Cave in UE5

Note: This article is a current work in progress.

Note: This was originally created on a google sites in October 2023, but has since been converted to a blog post here. It was originally in two separate parts and it originally involved the design, modelling and texturing of an idol in the middle of a room as well as the design, modelling, slicing and building the room. I wanted to document my progress here.

Designing the Idol

These are some references of Cycladic heads that were gathered to understand the shape and texture of the mode.

(carosel)

The initial idea for the design was to try to combine the Cycladic shape of the idol with a more Lovecraftian theme to make the idol seem it has supernatural powers hidden behind it.

Here are some of the Lovecraftian idols that were gathered as reference.

Frequent themes seen were varying amounts of eyes, abyssal engravings and different animal parts such as bat wings and tentacles coming from the mouth. These would be the main elements incorportated into the model.

I started out with a basic sketch of a Cycladic head then added other horror elements to give it the supernatural look I wanted. I wanted to keep base shape the same so I replaced the jawline with a tentacle mouth and added more eyes.

The sketch was detailed to add gold to the engravings and head, a old mossy texture to the rest of the figure, bone teeth in the tentacle mouth and glowing cosmic eyes. This was done as the carvings will be much easier to add in mudbox now that I understand my design more

Modelling the Idol

Initial Problems

A couple different approaches were made in modelling before reaching a useable model. At first I made the tentacles entirely in mudbox as seen below but when bringing into maya and substance, there wasn't enough detail in the low poly model to carry over the added information.

(image)

Before Mudbox

(image)

After Mudbox

The Solution

Instead, I modelled a couple low poly tentacles into a basic shape which would help when adding the information into substance later. I also added two more tentacles from my original design to add more detail.

Mudbox Detailing

Detailing Issues	A Solution	Finished Model	End Result
While adding the basic shape to the tentacles helped dramatically with the quality of the low poly model, there were still issues. The tentacles looked unusually boxy and the ends of tentacles were too different from the original model, causing clipping errors.	The decision made was to delete the ends of the tentacles and quad draw the low poly tentacles to the high poly.	While extra work had to be made to re-make the tentacles and UV map, the end result looks significantly smoother and realistic compared to the previous model.	The tentacles look much more detailed when carried over to substance painter and unreal compared to the previous image

Designing the Idol Room

I wanted to create a horror-esque room for the idol to be positioned in to add to the idea of a "supernatural Lovecraftian idol". My idea was to create a living environment that had taken over an existing one or been "swallowed". Rather than having a normal cave the walls and floors would be fleshy interiors and would feature a mix of alien like plants and structures as well as recognizeable human structures. The entrance/exits to these tunnels would have curving tunnels leading out as if they were intestines or tentacles.

(image)

(This was originally where the second part of the google sites post was)

A few reference images were gathered to improve the existing concept of the flesh cave from the first part.

A lot of smooth, organ/human like shapes are used in these reference images.

The colour red is a very prominent colour.

Long cylindrical tunnels seem to be used as if they were inside an intestine or mouth

A Redesign

The idol room from the first part had the required themes and ideas behind it but lacked interesting shapes or any real depth. The room was therefore redesigned with the original premise of fleshy tunnel paths leading to the room.

The New Idol Room

(image)

The room still featured the tunnels and alien pillars from the first design but however much more work was put into the celling to add more detail. Now a strong light shaft would come through a hole in the middle of the ceiling, giving the idol extra emphasis.

A Slice

To save on work later, the room was split into slices meaning it could be duplicated around into 4 connected pieces.

The Room in Unreal

The Slice was created in Unreal by using Rock models from Quixel Bridge and applying a flesh material to them.

A castle wall was used and also applied with a flesh material and a squid tentacle decal.

A saw blade was used at the top ceiling to hide the lighting for the spot light in the middle and other ambient lighting around the sides of the blade for more ambience.

The alien pillars was a candle model upscaled with a point light on top.

Afterwards the slices were repeated around to give the final shape of the room. At this point only minor touch ups were needed for the shape of the room. For example, rocks that were clipping through the roof and messing with the lighting.

Here are some unlit angles for perspective

Improvements for the Future

There were many things achieved through the process of making this environment and animation but there were plenty of room for improvements. For example, having an environment outside of the flesh tunnels would have added to the authenticity of the environment rather than a basic unreal landscape. More bespoke items should have also been added to the environment to add more detail and story.

The "Hero Idol" character's textures were also quite uninteresting and should have had both more detail and varying textures between the characters. The current texture set was also quite dark making it hard to see them in the scene. Time could have also been saved by not seperating the uv maps of the head and body.

There were also improvements that could have been made to the video. The tentacles hanging from the ceiling were originally rigged so they could pick up the idol more believably. However this was a little too ambitious as time ran short on animating them. Instead there positions were animated to go directly up as if they were retracting into the ceiling. A "laser" also had originally shot out of the idol when summoning the portal but unreal kept moving the vfx during the final render so it was removed, this made the portal appearing make less overall sense in the end. If this was fixed or an alternative was found this would have added to the video.

Published: Tuesday, 25 November 2025
Categories: 3D Modelling Unreal Engine 5