[#VWR-2968] Sculpted prim: Alphachannel data can bork your sculpt

1. Second Life Viewer - VWR

Sculpted prim: Alphachannel data can bork your sculpt

Created: 04/Nov/07 02:51 PM Updated: 06/Aug/08 10:41 AM

Component/s:

None

Affects Version/s:

1.18.4 Release Candidate, 1.18.5.3

Fix Version/s:

1.20 Release Candidate

File Attachments:

Pen case.rar (19 kB)

Image Attachments:

1. Alpha channel watermark bug.jpg
(124 kB)

2. bborked_snapshot.png
(135 kB)

3. fixed.jpg
(65 kB)

Environment:

win XP

Issue Links:

Relates

This issue Relates to:

~~VWR-2404~~ lossless texture compression on small textures not lossless

This issue is related to by:

~~VWR-3922~~ Sculpties/Sculpted prims rez differently after each login

VWR-5647 Meta-Issue: Sculpted Prims Need More Linden Lab Development

Linden Lab Issue ID:	DEV-5654
Linden Lab Internal Branch:	1.20.7.87883 RELEASECANDIDATE

Description

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Currently putting watermark data in the alphachannel can deform some of your sculpties.

The sculpt-preview shows it ok, after your downloaded it shows ok, but if you relog and clear your cache. 10/100 it will show correct, but 90% it will render incorrect. The model deformation only happened to certain sculpties I created.

Uploaded lossless at 128*128. This bug happened at

1.18.4 (1) Release Candidate
1.18.3 (70780) Beta Havok
1.18.3 (5) Release

All

Comments

Change History

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Acru Joliat added a comment - 04/Nov/07 03:07 PM

Adding data to the alpha channel can reduce the compression ratio, and trigger the lossless bug already reported (and fixed internally) in ~~VWR-2404~~.

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cel edman added a comment - 07/Nov/07 11:58 AM

Indeed it seems like the lossless bug handled at ~~VWR-2404~~. Only new thing here is that using data in the alpha channel can trigger the bug as well.

Quarl> our SL clients and servers assume that all of our images are encoded the same way - and use this to optimize image transfer over the network. (it thinks to itself - "i need a 64x64 image - that should be about 64x64x3 bytes, compressed at 8:1, so i only need to download 1536 bytes.") this sort of heuristic occurs in the sim code, the viewer code, and the cache code, in different ways, which causes a variety of failure modes.

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Qarl Linden added a comment - 08/Nov/07 09:54 AM

yeah, i suspect it's merely ~~VWR-2404~~. all that detail in your watermark is making the file bigger, and it's not downloading in its entirety.

Cel - can you send me inworld versions of these objects so i can test them against the ~~VWR-2404~~ fix?

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Qarl Linden added a comment - 08/Nov/07 03:09 PM

Cel - good news - your sculpties look perfect with the ~~VWR-2404~~ fix. photo attached.

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WarKirby Magojiro added a comment - 05/Dec/07 04:10 PM

Tested this in the new 1.18.6 RC which has the ~~VWR-2404~~ fix applied, as stated here: http://blog.secondlife.com/2007/12/05/new-release-candidate-viewer-1186-rc0-available-today/

The issue is not fixed. see Alpha channel watermark bug.jpg that I attached. 4 copies of the same sculpt map, with differing alpha channel data. The first, second, and fourth are perfect. The third, which has a watermark, is distorted.

[ Permlink | « Hide ]

Qarl Linden added a comment - 05/Dec/07 04:37 PM

WarKirby - i cannot confirm you're seeing a bug unless you attach the image files. please make sure they're in a lossless format.

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WarKirby Magojiro added a comment - 12/Dec/07 02:23 PM

Images attached in a rar archive.

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Harmpie Rhode added a comment - 11/Feb/08 09:17 AM

could this be the same as ~~VWR-3922~~ ?
Since he states that at first it looks ok, but after relog or cache clearing it gets borked and there seems to be a randomness in wich get borked and wich doesnt.

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cel edman added a comment - 11/Feb/08 01:39 PM

Harmpie the lossless bug still happens, the size in data of the sculptimage triggers it;

To prevent it from happening I:

scale my sculpties first to 32*32 (working with these points) then to 128*128 (nearest neabour)
dont put a logo anymore in the alpha channel
upload my sculpty at 128*128 lossless
I test in on the betagrid in an old client. If deformation happens, I simple edit and remove parts of my sculptymodel until it shows ok. Like I can make a wheel with 16spikes, or a 12-step stairs, but it showes deformed. Removing parts of the sculptimage/data until it works, like 14spikes or 9-stairs shows correct. The end result is sometimes a sculptimage that only uses like 2/3 of the image data, the other part just not used/same color.

http://www.xs4all.nl/~elout/sculptpaint/tuto/xxtips.html (Tip #05 - Invi Sculpties & the lossless bug)

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cel edman added a comment - 11/Feb/08 01:46 PM - edited

Duplicate of VWR 2404

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Harmpie Rhode added a comment - 15/Feb/08 10:41 AM

Hey Cel thanks for that tip, enlarging the sculpttexture to 128x128 does help a lot. They even look good in the normal viewer now, while before they never did. I now also just put a blanco alpha in, atleast I can sell my objects mod then, too bad I cant put my logo in anymore though.

Weird thing is that while enlarging the sculptmap to 128x128 does help for most sculpties, it seems that when the sculpt gets just a tad too complex it will still look borked in the normal viewer. Like I made a column that had three looks, one smooth, one profiled and one where the profile was also twisted around, the first two looked perfect when uploaded as 128x128 lossless, but the twisted one did not, atleast not in the normal viewer. While the amount of verticed used where the exact same.

Anyway I still hope they will fix this bug soon, its kinda limiting use of sculpties now.

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Theblack Box added a comment - 23/May/08 03:35 AM

Please check if this is still happening in SL-Viewer RC7 !
This seems to be a duplication of ~~VWR-2404~~

Information in the alpha-layer just makes it harder to compress an image ... which caused ~~VWR-2404~~ to occur due to not satisfying the old (wrong) file-size assumption.

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cel edman added a comment - 23/May/08 05:03 AM

Seems to be fixed now as well together with vwr-2404 in RC7

Got this complex sculpty; uploaded at 64x64 including a logo in the alpha channel,
and since latest RC7 it seems to load correct everytime.