Odd candle behavior in Prboom+

[Saint_Guy]

I'm working on my first project.
It's a boom mapset and I have been testing it in Prboom+.
For some reason that I cannot understand, two candles jump from where they are placed when a nearby wall lowers.



I could understand it if the candles boxes where overlapping the lowering wall but they are a pretty good distance away from it.

Here is a video of the behavior.
https://www.youtube.com/watch?v=FH9YxvpMYlA&ab_channel=SaintGuy
Using Prboom+ with latest Prboom+ compatibility setting.

[Memfis]

This often happens with objects that are too close to some border when floors start moving. The positions of nearby things get recalculated, sometimes leading to weird results.

If you're familiar with DEHACKED, you can try giving the candles a smaller radius. That will prevent them from "touching" the surrounding lines and maybe solve the problem.

[Linguica]

Looks like you've run into the bug discussed here: https://www.doomworld.com/vb/source-ports/72502-comp-floors-voodoo/

When floors move, the engine will try and update the position of all things touching the blockmap blocks surrounding the bounding box surrounding the sector (I think). This can lead to weirdness. Plus the MBF-added torque simulation is making the candle appear to launch itself for no good reason.

[VGA]

I think you can set the candles to have a radius of zero with Whacked. Then it will probably not be affected?

[YukiHerz]

Being an intangible decoration I guess there is no real point to it having a radius, is there any notable maps that have such issues with actor relocation based on sector height changes?

[Memfis]

Not sure if zero radius is allowed but you can definitely set it to 1. Though it will introduce another weird behavior. The thing is, you can only see a sprite as long as the object itself is within your line of sight. So if the object's radius is very small but the sprite is relatively big, there will be situations where you're supposed to see it but you can't. You can observe this effect quite well with large trees for example. But it's a smaller problem than moving objects I think.

[Saint_Guy]

Thank you all for the replies.
I don't really know about the differences in features between the Boom compatibilities are.
But Boom before the addition of MBF works and the candles don't move.
I have also seen that the candles move using vanilla comp.
If vanilla Boom (fixed?) this issue, why was it added in the default prboom+?

If default prboom+ uses a lot of new features that i'm not aware of, my map doesn't seem to use any of them.

I'm probably just going to ask people to change their Comp settings when playing the wad, when I finally release it.