0007377: Creatures with extreme sizes sometimes spawn with low mass and attacks pass through them -- overflow? - Dwarf Fortress Bug Tracker

ID	Project	Category	View Status	Date Submitted	Last Update

0007377	Dwarf Fortress	Creatures	public	2014-07-16 04:35	2014-07-16 07:55

Reporter	Wimopy	Assigned To
Priority	normal	Severity	minor	Reproducibility	random
Status	new	Resolution	open

Summary	0007377: Creatures with extreme sizes sometimes spawn with low mass and attacks pass through them -- overflow?
Description	While making modded creatures, I noticed that sometimes, those with huge sizes (around giant sperm whale size, but earlier as well) spawn without any mass and most of the time, attacks only pass through them. Their low mass is shown that if a much smaller enemy charges at them, these supposedly enormous creatures will fly away at very large speeds. This behaviour is also exhibited by giant sperm whales in an unmodded game. It does not happen all the time. Even with two giant sperm whales spawned after each other, one may work as it should while the other will be a 'phantom' version. I have not been able to confirm if this also happens in fortress mode or only in the arena.
Steps To Reproduce	In the arena (easiest to find) 1. Spawn a giant sperm whale. 2. Spawn anything else. 3. Control the non-giant creature and attack the giant sperm whale. It should produce the bug, but this does not happen all the time.
Additional Information	It has been around at least since 0.34.11 and even now in 0.40.03. I am using the SDL version.
Tags	No tags attached.

Talvieno 2014-07-16 05:19 manager ~0026615	Can confirm this for arena mode, specifically for the giant sperm whale.

UristDaVinci 2014-07-16 07:24 reporter ~0026628 Last edited: 2014-07-16 07:25	The actual maximum size due to a size cap at RAW-reading time is 100,000,000. BUT It is possible to wrap around your creature size to a negative number using CHANGE_BODY_SIZE_PERC to get a size larger than 2147483648. CHANGE_BODY_SIZE_PERC is not affected by the above mentioned size cap. In 0.34.11 at least this was automatically increased to the minimum size of 1. The Giant Sperm Whales use CHANGE_BODY_SIZE_PERC. Having miniscule volumes and contact areas on body parts is known to cause attacks to "pass right through". This also happens if you create a weapon with a contact area of 0 in the ATTACK token. As a side effect of the tiny volume, the mass is also tiny.

Wimopy 2014-07-16 07:55 reporter ~0026630 Last edited: 2014-07-20 08:48	I think you wrote the same on the forums, but I still believe it warrants a bug report, if not for else, then for a revision of CHANGE_BODY_SIZE_PERC or giant sperm whales. Also, with modded creatures, this happened without using CHANGE_BODY_SIZE_PERC, so that can't be the only problem. (I can't remember what the size was that I used at the time. I'll look into it and update. It might have also been a different error, I'll do some tests then update) EDIT/UPDATE: Setting BODY_SIZE over 200'000'000 causes the bug/overflow to happen. (This was tested by modifying sperm whale raws) 250'000'000 seemed to make it more common than 1'000'000'000. UPDATE2: It seems that with BODY_APPEARANCE_MODIFIER tags set to a fixed value (I tested 100, 105 and 95) I couldn't get the bug/overflow to trigger. Though I don't know how that changes giant versions of animals.

Date Modified	Username	Field	Change
2014-07-16 04:35	Wimopy	New Issue
2014-07-16 05:19	Talvieno	Note Added: 0026615
2014-07-16 07:09	~~user6~~	Relationship added	related to 0000787
2014-07-16 07:10	~~user6~~	Summary	Creatures with extreme sizes sometimes spawn with low mass and attacks pass through them => Creatures with extreme sizes sometimes spawn with low mass and attacks pass through them -- overflow?
2014-07-16 07:24	UristDaVinci	Note Added: 0026628
2014-07-16 07:25	UristDaVinci	Note Edited: 0026628
2014-07-16 07:55	Wimopy	Note Added: 0026630
2014-07-16 08:41	Wimopy	Note Edited: 0026630
2014-07-20 08:48	Wimopy	Note Edited: 0026630