[kami]

hi.
i got a problem with a project ... suddenly all materials in the scene have disappered (in the scene manager AND in the library). the weird thing is, that rendering works fine, but I have no idea how i can access and export the materials. i wanted to render the scene on a different computer but there the rendering did not work for lack of materials.
on the image below you can see, that some materials assigned to layers are not listed in the scene manager or database. i added a few new materials later, but the list has been completely empty.


thanks for your help!
greets, kami

[JDHill]

The only realistic way I can think of for this to happen is for you to have explicitly deleted the materials using the Database Manager. Neither a plugin, Rhino, nor a disk error could cause such a thing, since materials are always saved redundantly in the document. The only way to get to a place where they are in neither the database nor the document is if both of the following were true:

1. you deleted materials from the database
2. you then saved the document

A database or disk error alone would not be sufficient to accomplish this, since backup copies would still be saved directly in the document, and the database would be fixed up next time you opened the document. Does this help explain the scenario, or if not, do you have any more clues I might use to figure out what you're seeing?

[jvanmetre]

Kami-

I've seen a similar issue but in much earlier releases...materials disappearing for no clear reason. I think it came down to not enough memory in my system (2 gb max).

When faced with lost materials in a scene I resorted to using the last mxs in studio and working with it in there...not that you want to, but you can export materials from studio as well. It may not be worth the trouble but once you export the material you could go back and assign in Rhino.

jvm

[kami]

@JDHill
I am pretty sure I neighter deleted them from the database manager, nor from the scene. If I would have done that, the file wouldn't still render ok on my machine?
Sadly, I cannot copy what I did, because I didn't notice right away when it happened. But I had several experiences before, where my database was reset. It's not grave because I don't use it in the way it's supposed to be, but only to reuse materials from an old project and never bothered to keep any order in there. But it has been emptied for several times now. Maybe it has something to do with the fact that I often work on two different rhino files, having them both open at the same time.

@jwm
thanks for the suggested solution. that might work and I'll try it later.

[JDHill]

Hmm, well it's a bit confusing then. You can delete them from the Scene Manager with no effect on the database, but not vice-versa. So I guess, I would need some more info, in particular, about how you say the the file renders ok on your machine - when you look at it in Studio, are the materials really there, or are they ones automatically generated by the plugin during export? Because really, materials should either be there or not.

About Jim's issue, if I remember correctly, this was due to problems when materials had the same name, but with different casing; it no longer matters whether names are unique or not, so those issues should not be present now.

[jvanmetre]

Kami-

I avoid working with multiple sessions of Rhino + MW at the same time...too many problems with reduced system resources, leading to problems ie. materials being assigned, then lost when the file was reopened.


jvm

[kami]

well. they are really here ... i opened the file in studio and they are all shown as before (inkluding all settings as real scale and coating etc.).
now i exported them as suggested and am reimporting them again

[Fille]

Hi guys!

I have to say that I have experienced the same thing - disappearing or automagically (?) altered materials - when working with two (or more) Rhino-sessions open and when working on two (or more) computers with the same files. I do usually have more than one Rhino open at a time (containing materials with the same name, but different properties in the different files) and I'm also using more than one computer (at work and home) - every day. I've learned to empty the database for a file before I open it on a different computer. If Maxwell automagically would do this for me it would help - I don't always remember myself and have to exit Rhino and start over... - but even when I remember, I have had disappearing and oddly changed materials.
I'm sorry not being able to give you a specific step-by-step instruction to repeat this, but something funny is going on with materials and the Database Manager... Sorry JD. If I can think of anything more specific I'll let you know.
Hmmm, this probably didn't help much, did it...

Philip

[JDHill]

Thanks guys, I passed over Kami's mention of using multiple sessions, and I hadn't considered that as a source for the issue. Working this way could provide for some difficulty, since the database in one session doesn't know about the database in the other one - yet they need to work with the same set of files. I have to make some pretty fundamental changes in the plugin to get around this.

[jvanmetre]

Fille-

How are you emptying the database?

[jvanmetre]

JD-

I'm going from memory but when you copy a part from one session to another and both files have the same material name, my experience has been that Rhino allows it to copy with the same name, so you end up with two materials with the same name in one file...that can't be good.

jvm

[Polyxo]

Good to see this discussed. I also experienced weird material disappearing and could not isolate the reason.

[Fille]

Hi

How are you emptying the database?

Open the Database Manager, right-click your file(s), click "Remove"...


Philip

[jvanmetre]

Didn't think you could do that in database manager...now I see you can.

Thanks.

jvm

[kami]

until now i only used the database to quickly access materials i've used on different projects before. but i always copied them, to prevent me from changing the material for the old scene.
but in this case, its strange that some materials aren't shown in the database nor in the scene manager. since they export correctly, they have to be stored somewhere... would it help if I provide you with the .3dm in question?