Destruction Overview Part 2 - Building Impacts

Following up on our look at Destruction Modelling & Fracturing, our art team is back with a look at FX and building impacts! Enjoy today's post from Michael. - JohnT_RE

Hello everyone, I’m Michael and I’m the Lead FX Artist on CoH 3 and I created the majority of FX on CoH 2. I’ve been asked to follow up on the great writeup that Patrick did about CoH 3 building destruction.

Today I’d like to share some new weapon impact tech we’ve recently added to our buildings pipeline. Inspired by a ton of real life and movie references, (specifically that scene in Fury where the tank blasts the building) I was looking for an opportunity to really improve our building combat. CoH 3’s new building cell tech finally allowed this. 

Company of Heroes 1 & 2

In the past, weapon projectiles would hit a building’s ‘bounding box’ which, as the name suggests, is a box that is used by the simulation to detect our impacts. This can lead to some obvious popping when a building is hit by a weapon and the FX aren’t large enough to cover it all. 

Company of Heroes 3

Using the new cell tech, as a cannon round impacts the building, we trigger the impact effect as normal off the old bounding box, but additionally the sim now calculates (based on the weapon’s area of effect) which building cells are damaged and triggers effects from each affected door and/or window. 

The result is a more spectacular impact which helps to hide any obvious popping of geometry, keeping you immersed in the battle. 

Now that this tech is live, I have plans to expand the FX variety to the other munition types: flamethrowers, artillery, etc. Once those are in, we polish, polish, polish! 

Thanks for all your feedback, I really appreciate it! We love this franchise as much as you do and are working hard to give you the best game we can. If you have any questions about how we implement FX in CoH 3, I'd love to hear them!

- Michael

Hello Michael and @JohnT_RE ,

This is cool, thank you for sharing this new impact tech, it's easy to forget how much these details impact the experience, but you said it perfectly "keeping you immersed in the battle" indeed.

Coh 1 video - It definitely looks 2D and more scripted "destruction fragments" but considering the year was 2006 it's actually quite impressive in its own right. 16 years ago and the foundation and design is there clear as day. The building does look painted on opposed to depth 3D miniature building we now can appreciate.

Coh 2 video - Every shot has an impactful appearance to it, looks realistic too as this building is very much larger than the first example. The tank does appear to have more jerk depending upon the direction the barrel is facing. I did like the other sherman just cruising around in the background.

Coh 3 video - This is good, I like the building appearing 3D on impact opposed to just an animation and the bricks impact (you called building cells) from the shell damage. It looks good and I'm sure still a work in progress, I cannot wait to see the final polish in game. I agree w/ @Munte it is sort of hard to see exactly where impact occurs, almost near that corner window but as I mentioned in another post is hopefully the bounding box doesn't have to stay squared up 4 posts but floors or sections can be torn out to look like missing sections corner of the building just open gapped. That's a wish list but if I had any wish list for FX to buildings that would be it. 

Sound is key for these features to really draw in the player too like the reloading of the ammo or turret turning. Sometimes it sounded as if it was more glass than actual rubble but I know that's not FX but sound department but just feedback. When the sound thunders timed with the impact of your new tech it's the chef's kiss (al bacio) of destructive impact for the gamers viewing pleasure. 

I watched your reference Fury scene where the tank blasts that house at the end where they make their last stand. I love that movie btw but one thing I did notice was during the shermans vs. Tiger scene they rushed him and it was one shot kills for the shermans insta-killing entire crews. The reason I bring this up to you is hopefully these tank shots in the videos don't necessarily squad wipe the occupants of the buildings in Coh 3. I know that's not FX realm of influence, but it did make me think hopefully squad wiping isn't common place related to the destruction. Back to the movie Fury, I watched that final scene several times as it's really a quick flash sequence of that house near the end, but I did notice two things that stood out to me the most. The actual structure wasn't really shown crumbling on impact, it was the light impact on the infrastructure actually surprisingly like they shot it through window and it impacted inside the building opposed through the wall, so what stood out to me was almost like a haunted house flash where all windows light up and dramatically show the explosion through lighting. The second thing that stood out to me was the fire, I think in this movie he mentions Willy Pete (white phosphorus) so they were playing to the fire damage specifically where I know your videos weren't showing that sort of ammo yet. Anyways it'll be interesting to see as you said how you expand to other munition types, I think besides the sound I mentioned, visually the lighting and smoke will be two most important components for the FX. Keep up the great work Michael, it's impressive uncharted territory you're carving through with these latest features, it's looking good.

- Art of War

I am sure you are aware that there is a frame when the second shot hits where the building appears to be undamaged again. Still wanted to point it out because it is quite noticable.

The overall effect looks nice, however like in the first video I still find it odd that there is all that debris falling and yet nothing of it remains on the ground except for three or four smaller pieces.

Where did the balconies go and all the bricks?

I know you have to optimize for performance, but generating a damage model that aims to look so authentic at first glance (dust coming out of the windows, smaller bricks falling out of walls etc) and then breaks this illusion so quickly on the second (most of it simply disappearing without being there in the game world) is almost worse than having the semi-authentic effects of CoH2 in the first place because these do not disappoint my expectations.

Don't get me wrong: All looks better than CoH2, obviously, and even without being a programmer I can imagine how much work it was to come that far and I want to congratulate all of you on that work. But I sincerely hope that there will be more focus towards logic consistency, even if this means scaling down the amount of debris from the first impact. Generating 100 debris bricks and only keeping 5 looks overall worse than generating only 20 and keep the same amount.

Still imo feels a bit off.

Dust comming out of every single window, while shot is clearly hitting the outer wall of the building.

Dispite tank hitting the wall, small derbis falling off like if the explosion happened inside the building

Still really strange to see random parts of the wall falling out, like if they are made of lego. 

The point of impact has no clear destruction, while shockwave knocking out random wall parts.

While CoH1\2 damage systems were infirrior in complexity, as it stands right now they look much more belivable and realistic in terms of what kind of damage done you expect to see after tank fired at it.  

Ideally, after being hit, circular shape like hole should appear (simular to CoH2) and small chunchks around the hole should fall down. Key part being that all damage should be near the point of impact and the point of maximal damage, not like if building was just hit by a massive shockwave or an earthquake.