Smoke/chem grenade capture glitch explained.

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rift
Posts: 48
Joined: Tue Mar 28, 2017 9:36 pm

Smoke/chem grenade capture glitch explained.

Post by rift »

Sometimes you toss a smoke grenade thinking that your units will receive the defense bonus, just to find out later that they did not...
After a lot of testing, I figured out how the smoke/chem radius works exactly, and why it glitches out sometimes.

Here is a video I made that shows the gist of it, but the post below has additional detail. In the video you'll see a smoke grenade where two soldiers were highlighted and didn't get smoked, and another soldier who wasn't highlighted DID get the bonus.

https://www.youtube.com/watch?v=PPT6Tng ... e=youtu.be

When aiming a grenade, the visual AOE (area of effect) indicator, a.k.a. the ‘aim bubble’, highlights all units within range of the grenade. In rare situations, a unit standing on the outer edge of the AOE bubble may appear to be highlighted, but they may actually be outside of the AOE, and will not receive the smoke/acid status effects. The reason for this apparent bug is twofold.

1) The bubble has the shape of a hemisphere which appears as a circle on the ground, while the actual AOE consists of an exact number of square tiles on the surface, i.e. no partially covered tiles (examples shown below). In other words, the actual AOE is bounded by the straight edges of the affected tiles, so it's not a circle. In many cases, especially on maps with cleaner terrains, a dim outline of the covered surface can be seen flashing over the ground.

2) The position of the actual AOE is determined by the choice of the center tile (the tile where the grenade lands). The most important thing to pay attention to is which tile the grenade lands on, regardless of the exact location within that tile. The tile in which the grenade lands on, is the only thing that determines the resulting area of effect.
On the other hand, the aim bubble moves precisely with the mouse cursor. If you move the mouse cursor within the boundaries of a single tile, the aim bubble also moves around and changes which units are highlighted, even though the actual AOE remains unchanged. If the cursor is, for example, very close to one of the corners of the tile, the aim bubble will “spill over” to external tiles that are not part of the AOE, and it will erroneously highlight units that are not in the AOE.

Here is the actual AOE of smoke/acid grenades
https://postimg.cc/image/lxjuspx6b/

The next image shows an example diagram of the inconsistency, where the aim bubble highlights the wrong tiles. The radius is 5.6 mobility points (UFOpaedia), which corresponds to 3 straight tiles or 2 diagonal tiles. The red circle represents the inaccurate aim bubble. The center of the bubble (mouse cursor) is positioned near the top right corner of the destination tile. As a result, it will highlight the two units (marked by green X’s) standing outside the actual AOE.

https://postimg.cc/image/cd2iol8fn/

The best way to avoid uncertainty is to count tiles. Given tile pattern of smoke/chem, you can tell exactly which units can actually fit inside the AOE, and you can determine which tile should be the center tile. Just send the smoke/chem grenade to that tile. Ignore the aim bubble. This always works.
Last edited by rift on Sun Jan 30, 2022 4:53 am, edited 18 times in total.
caseywills
Posts: 28
Joined: Sun Apr 02, 2017 1:45 am

Re: Smoke/chem grenade capture glitch explained.

Post by caseywills »

Thanks!
rift
Posts: 48
Joined: Tue Mar 28, 2017 9:36 pm

Re: Smoke/chem grenade capture glitch explained.

Post by rift »

I'm glad this was useful to someone :)
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