UE4 Acid Explosion WIP

Jimster092

Hey guys, so I've been working on a stylized acid explosion effect in UE4 and would love some feedback before I get into polish stage. I'm planning to have this as an ability, in which the character throws out grenades radially around him to prevent his enemies from running away. I think the only issue that I ran into while capturing was my flare texture not loading. Other than that, this is what I have so far!

[ame]https://www.youtube.com/watch?v=dIsl7J-hbZg[/ame]

nickcomeau

That's a pretty cool explosion! I guess right now the circle that comes out first is a bit too even I think, I would either fade it quicker, or make it expand faster I think.

Jimster092

Alright, I'll work on the timing for the ring. Thanks for your reply! I'll post an update soon

Jimster092

[ame]https://www.youtube.com/watch?v=MZ5Q-2rYkiQ[/ame]

Aside from the grenades falling through the floor and the textures not loading in the first part of the video, I updated the effect with just a fluid flipbook. Multiple attempts in RealFlow(Still Learning) but this was one of the better outcomes. Not sure if the fluid is lasting long enough or is too visible? I also created the second part just for context purposes as if the grenades are raining down on the enemy, something similar to Borderlands.

The next step is to polish and paint some of my textures like the Density and Temperature of my explosion.

nickcomeau

I think it's looking spot on right now. I think the timing is pretty good. Maybe make it a little less visible?

Christian Nordgren

I think it looks great, you should consider having a darker background to make your vfx standout more

Ged

very good, acid doesnt seem burny enough to me, more just glowy and shiny, maybe there are some things that would help imply the danger? could you leave a burn mark with some steam coming off it after the acid is gone?

Jimster092

@Christian Good idea on the darker background, I'll make an adjustment to the level to better suit the effect!

@Ged I'm gonna repaint my acid texture over (just started to learn how to paint haha) Hopefully I can sell the hot, acidic look of acid. Burn mark is a good idea and the smoke is easily accomplished by reusing one of the smoke emitters I created.

urgaffel

Nice effect! I think the lens flare is a little bit over the top especially when you have multiple grenades going off; you can't actually see the effect and once the flare is gone you're just left with the pools on the floor. Personally I'd also
prefer a static camera rather than a rotating view but that's just me.

Some more points:

The shockwave looks a lot like an expanding glass bubble, maybe make it thinner so it's less like a torus and tone it down slightly?

The green liquidy bits could live for a bit longer as they're trown out, it would make your mind connect them a bit more to the pools on the floor

Smoke rising from the pools and scorch marks are a great idea. See Alien/s for good example of acid eating through things (Alien Resurrection when aliens kill another alien to escape is a good one too).

The round glowing things are quite uniform in shape and size, could do with some more variation or possible fewer/more variation in velocity... Not sure.

The area of the pools of acid at the end are a lot smaller than the explosion implies, I'd make them slightly larger or have it change depending on at what height the grenade explodes (trickier but would be more dynamic). If the grenade explodes in the air like your first single one does, you'd have a larger area of acid. If it explodes on the ground it could be smaller. Another thing that you would be able to do if you made the area dynamic would be to have it stick to walls and then slowly slide down. Lots of potential there...

Jimster092

@urgaffel Right when i saw your post, I made the adjustments! Toned down the lens flare in my scene camera and scaled the specified elements like the acid pools and slightly thinned out the ring. I made my distortion ring scale out a little bigger just so it doesn't interfere with the impact ring itself.

I wish I was more savvy in blueprint to create something that correlates with the explosion height.

I had the same thought about making the acid act as a decal but would that complicate the location spawns for my bubbles/ripples? I have a feeling those smaller elements wouldn't be able to be used as decals.

Jimster092

Repainted some of my textures and re-simed a different smoke texture along with a more accurate smoke normal map. Hoping this is near finished, but still open to critiques before i finalize it. Toned down the lens flare in my scene camera. Should I tinker with those GPU particle collisions? I had Scene Depth Collisions enabled hmmm

[ame]https://www.youtube.com/watch?v=X753bhBf3u4[/ame]

Maxilator

This might be irrelevant to you, but I programmed particle systems for a game in a custom 3D engine a while back and noticed that adding sound changed the perception of the explosion quite a bit, even if its not sound design you are working on I'd recommend just having at least some default explosion sound to replicate how it feels in a game. It might seem trivial but, for me, it really changed how I viewed the explosions.

Jimster092

@Maxilator Sound is definitely a huge player when it comes to the overall effect! I would have a sound cue play every time it goes off in blueprint but I render out my effect through frames, which disregards sound...I plan to put sound in the end though but it probably helps if I put some sort of sound there in the upcoming updates to sell the overall explosion.

Jimster092

Pretty happy with what I have now. Tweaked some small things inside the emitters and put in some LODs. Added sound to tie everything together. Is there anything to change or add before I near finishing it? I'm probably going to end up making some debris for small metal chunks.

[ame]https://www.youtube.com/watch?v=EUGtPQ8xDwM[/ame]

Ged

cool, the only thing that stands out to me is the glowy acid blobs dont look 'splatty' or detailed enough, I would expect a little bit of spray around the main blobs

Jimster092

Are you talking about the blobs in the center of the explosion? If so, i could add another pass for another liquid element.

Ged

Jimster092 wrote: »

Are you talking about the blobs in the center of the explosion? If so, i could add another pass for another liquid element.

no I mean the splat that glows after the explosion has gone off, the one shown in the preview pic on the youtube video before you press play

Jimster092

Ahh I believe youre talking about the green sparks. Those were mainly from the combustion of the explosion. I mainly have 2 liquid elements in the explosion: 1 is viscous, which is in the middle and the second are the stringy sprites are what stems off of the middle. What I'm trying to sell is a very thick and viscous fluid overall but I'll look over the effect to see if some splash would be needed.

Jimster092

[ame]https://www.youtube.com/watch?v=-Ylmms3Xj28[/ame]

Welp, here's my finished product. I added a few small bits of debris from the grenade and added an angled top view for perspective. Thanks for the feedback guys! I hope this holds up as a cool effect for y'all

urgaffel

That's a good effect. I had a few pointers I was going to post yesterday but didn't have time. I can still post them if you want?

I belive Ged was talking about the puddles on the ground, that they needed some drops outside the main blob to make it look a bit more detailed and less blobby.

Ged

urgaffel wrote: »

That's a good effect. I had a few pointers I was going to post yesterday but didn't have time. I can still post them if you want?

I belive Ged was talking about the puddles on the ground, that they needed some drops outside the main blob to make it look a bit more detailed and less blobby.

yeah thats what I meant it looks pretty good from top view though. Nice work.

Jimster092

Ohhh! Thats what you meant! If I knew haha, thanks though! I think I spent too much time on this one effect, so its definitely time to keep moving. I appreciate everyone's feedback for sure.

@urgaffel and I would love to hear those pointers. It doesn't hurt to learn a thing or two for next time!

urgaffel

Alrighty, here goes:



So the two shockwaves is what makes it look like it's inside a glass bubble like I mentioned earlier. I'm not sure what's going on there to be honest.

The sprite looks really low res and is cutting through the floor, there are ways of getting it to fade the edge so it's softer, usually called depth fade.

The smoke from the acid pools could be more tendril-y and a bit more uneven in height (just add random), at the moment they're all more or less the same size.

The green sparks are a bit too glowy, and I'm not sure if they are sparks or drops. If they are drops maybe tone down the glow, if they are sparks I guess leave them as is?

I still think the glow is too strong but that's just my opinion You can see the floor darkening quite a lot when the grenades are going off but I guess that's also down to the eye adaptation/post process things.

One last thing, the angled camera has a lot of empty space at the bottom of the screen, the framing could be better to show off the effects more.

Jimster092

Wow this is a great breakdown. One of the shockwaves was a distortion ring that scaled slightly faster than the other shockwave. I probably couldve changed up the texture/color to make it different. For the low res sprites, it always happens when the beginning of the level loads, so I'm not sure how to deal with that. And I do have Depth Fade inside my shader for that material , so I'm not sure if it's just the loading that's causing that. I believe you can see softer edges later in the video.

From your paint over of the smoke, I definitely agree. This will taken into for future smoke like that!

Overall your advice is fantastic and really will make me think of details like that for my next effects. You will see me in the forums again soon, so I hope to hear from y'all again!

urgaffel

Glad I could be of help

The distortion and shockwave work well, it's just that the way they are in your effect makes it look a bit weird. A way around it could be to make the distortion ring thinner so it's not quite so pronounced and/or to make the distortion even faster since the distortion shockwave usually travels a lot faster than the explosion (lots of reference online for that kind of stuff). It will be interesting to see your next effect.