Major Features
*The following description was pulled from the full Grenadier post which features dozens of pictures and recounts my own build process and more clearly shows off all the features for this helmet, it can be found here*
 
Unique, Easy-To-Assemble Design.
This helmet was designed to fit together like a 3D puzzle. This model was originally comprised of 40+ pieces, but now accomodates over 80! (Parts that can be mirrored are included as singular models w/ instructions to reduce file size). All of the large major pieces are designed to snugly fit together utilizing aligment pegs that allow for the helmet to be securely assembled/dissembled without the need for screws/glue. Some of the smaller accent pieces require glue to place in their slots, but outside of that, this helmet is printable in such a way that a vast majority of the pieces do not require glue to assemble, this ensures that there are no ugly seams to hide/sand away.
 
Below you can see two pictures, both show how the helmet slides together one piece into another. The first picture show how all the "central" pieces slide together from the front.
The second photo shows that all the "side" pieces slide in from the sides and lock all the rest of the "central" pieces in place.
 
The optimal order to assemble the helmet can be found in the video at the beginning of this post.
 
Helmet Customization
This model features the most customization of any of my helmets. The model features 4 separate attachments that can added and removed at will. All attachments as well as their attachment features in the main helmet can be mirrored to be attachable to either side of the helmet.
 
Additionally, there has been a massive functionality update that includes ventilation systems, lighting systems, and speaker systems.
 
UA
The helmet comes with a stock version of the overhead visor and one that accommodates the UA attachment. There are additional versions that accommodate overhead fans for cooling/venting, but I will talk about that in a later section.
The overhead visor is able to swapped out on the fly as it slides in from the side and is locked into place by two, printable, hex-key compatible screws.
 
HUL
The HUL attachment comes in an easy-to-print 2 part assembly. The front plate and back body are printed separately and attached via 4 small alignment pegs. This allows for printing both pieces without supports.
 
HUL[3]
While the HUL[3] attachment is not available for the Grenadier helmet in-game, I thought that there was no need to limit this model (plus I had recently modeled it for my Commando Helmet which you should absolutely check out). The attachment features a multi-part, sleeved design that locks together using insert-able antennas in the back.
 
CNM
The CNM attachment also features a multi-part, glueless design that only requires a small drop of glue to attach side button.
 
Functionality Update
I've never included space specifically dedicated to internal electronics and would supply them on a case by case basis when requested. That all changed this past week when I decided that with all the many features I have added to the Grenadier for private requests, it was time to release an updated version of the helmet.
 
Removable Chip Insert
It was brought to my attention that the Reach version of the helmet does not feature the AI chip insertion feature like the Halo 5 version does. I included two seperate versions of the large main cap and the top of the neck to allow others to make a choice as to what version of the helmet they want.
 
Ventilation System
The newest feature, and the one I am most excited about, is the added ventilation system. The side plates and cheek plates now feature a square slot to fit hobby duct fans. This slot is connect via duct to the front of the helmet, where there are several options for small printable vent covers. The slot is a 52 mm square, so it should be able to fit 50mmx50mmx15mm duct fans with ease.
Here are some pics of the two printable vent covers.
 
Additionally ventilation was added to the top of the helmet and is only usable with the UA attachment. The slot is a 42mm square and should plenty of room to attach a 40mm hobby fan.
 
Forward Lighting Accommodation
Directly underneath the side duct ventilation is a separate channel and casing to accommodate various lighting fixtures of your choosing
 
Integrated Sound System
Each ear piece comes with a circular hole to easily insert 40mm hobby speakers. The hole is 42mm wide and features a large bottom square feature to allow for wires to easily pass through.
 
Visor Insert Features
The inside of the helmet features Guides to hold the visor in place. While the visor can sit on these alone I would recommend a low strength glue or tape to help fasten hit while still allowing you to remove the visor.
 
Sizing Ring
Model includes a sizing ring to help you scale the helmet to fit over your head. Sizing ring is equal to the size of the throat of the helmet so make it so you can fit your whole head through without slicing your ears off. In my case, I was able to print the whole helmet at 93% scale, which saved plenty of time and made for a better fitting helmet.
 
Multiple Visor options.
This model includes a full kit to help you make a mold capable of casting a resin visor. A resin visor in and of itself will have some reflective properties while more importantly allow you to make the visor see-through and a color of your choice. It also allows for more complex geometries than vacuum forming and makes for a sturdier visor. I went with a simpler mold shell design without an alignment baseplate for this design. The visor and mold shell sheathe together, so just ensure that the visor plug is not touching any of the walls before pouring in the molding agent. As usual, I recommend glueing the two pieces to a flat piece of cardboard. The mold shell is designed to be able to flip over and stand flat when pouring in Resin to ensure the top does not leak or pour resin.
Visor Resin Volume: 192 mL
Visor Rubber Mold Volume: 621 mL
 
You can find a more detailed explanation of the resin casting process in my "Builds" section.
This visor also comes with something I've never added before, a visor buck.
This will allow people who prefer a vacuum formed visor to do so.
 
Smooth Ergonomic Interior
This helmet has a large smooth internal cavity that makes for a very comfortable feel. Adding padding takes it to the next level.
 
If you would like to download demo versions of any of my models, you can find them here
 
You can read more about this model and my experience building it here.
 
All my models are designed with a focus on hidden seams, ease of assembly, little to no support printing, and accuracy in mind.
 
If you need any help with the printing or building process, or you just have a prop you would like to see me do, feel free to email me.