Part Smoothing - Where Do We Go From Here?

[Ben Supnik]

Hi Y'all,

I'm sorry to start a third thread on part smoothing, but I wanted to step back and ask a process question; I haven't been involved in LDraw long enough to know how this gets sorted out.

There are a few ideas that have been thrown out on how to solve part smoothing problems, but they involve different groups of people and perhaps different standards bodies:

1. We might say that no change to the LDraw format or any parts or any change to authoring guidelines will happen, and programs need to take the most drastic steps while smoothing, e.g. code for the worst case.

2. We might intentionally modify the parts library, perhaps with mechanical transformations (E.g. run a program that splits T junctions over many parts). This would require some kind of approval.

3. We might intentionally introduce new syntax features into the LDraw file format (and then apply them to some parts) to simplify the process of smooth rendering.

Where do we go from here? Would it be useful for me to write up an RFC, just so we have a straw man?

I can continue coding assuming case 1, but such code will be non-optimal (e.g. we'll have to put in a part cache that we don't otherwise have just to make things performant) and such code would be obsolete if either 2 or 3 happen. If either 2 or 3 are on the table, it would be nice to plan for them.

cheers
Ben

[Roland Melkert]

I've been working on LDraw programs (with pauses) for over 10 years now, and in my experience it's best to hope for the best but prepare for the worst

Also if more programs apply smoothing some of the parts will eventually 'automatically' get fixed by the part enthusiasts to make them look better in their favorite tool. So over compensating might actually be a bad thing.

Currently I tend to do corrections as far 'normal' performance allows it, In my older renderer i used to disk cache the unique point preparations, while LDCad does everything real-time using multiple cores now. The is the direct result of PC speed progress, fact it can be done fast enough in real-time, made me want to add smoothing in the first place.

So in short:

#1: It's largely up to the community I think, in the meantime tools need to compensate to the amount authors find doable/necessary.

#2: I'm sure any well tested mass correction / authoring tools would be welcomed by the library admins / part authors.

#3: I do think a smoothing (bfc like) direction meta could make useful addition to the spec, but it needs to be thought out deeply in order to decide if it's worth including. So it could take some time until it's available to the authors of both parts and tools. On the other hand the problem areas seem to be mostly detailed curved areas, something that can also be addressed using the new texture extension. So maybe it isn't even worth to fix the 'past' I haven't tried including the hard edges while smoothing yet though, so there might be some grounds for useful meta direction with those.