Future City: Update 8 - A Mixed Bag

I haven't managed to write anything this last week (or two) due to other things going on in my life (shock!), and not really feeling like I've been focused on one particular thing.  Instead of a themed post let's just have a look through what's been going on.

Refinement Fixes

Spent some time tidying up the city a bit.  There are a few places where detail refinement was being blocked so I investigated those.

• Empty Stacker recursion procedure leaf nodes were not ignored.

Stacker Merge appears as leaf when no further content needed, but should be ignored as not a geometry producer itself.
(excuse low-res image, Cairo scaled it down because the GraphViz output was too large)

• Temporary general triangle fill added for rooftops didn't support refinement.

Roof triangle refinement - before and after

• Bolts had bounds that were too large, needed to be pre-shrunk.

Bolt bounds blocking refinement - additional re-size in procedure to fix

• Mesh primitive operators were not being counted as geometry producing (which broke the fix for the Stacker recursion issue above).

Post load checks to classify operators by whether they modify/produce geometry or not.

• Unnecessary deep refinement of surfaces meant a deluge of synthesis when you strayed very close to a surface. This was slowing things down a little so I added a limit check in the sub-division process.

Adding a refinement limit test, whilst also abstracting out the recursion check to make it more re-usable.

To help track down some of these I added a bit more error diagnostics information:

• Capture errors show in view panel for selected node
• Error filter slider for when too many to display at once
• Any bounds information in the error messages is visualised in red

Additional error diagnostics - better messages, error select, and bounds rendering

More Girders

Couldn't resist more girder improvements as this has become a bit of an 'extreme detail' test case.

• Washers under nuts
• Proper facets on bolts
• Threads on the bolts (hacky, but fine for now)

Washers, faceted nuts, and threads.

• Added cross bracing to girders
• Fillet pieces for cross bracing

Cross-bracing and attachment fillets

• Added rolling fillets to I-beam section
• Added welds to fillets and fixing plates

Welds and I-beam section forming fillets

All a bit excessive, but some good tests of the detail management refinement systems.  Several issues and bugs were surfaced from this work.

The Wilderness

To make the city more interesting, and provide more of a 'setting' for it I decided to surround it with a Rural district type.  Currently just green/grass, this breaks up the city tone and gives it a rounder appearance.

Rural district type now surrounds the city.

This will provide something to have as the backdrop, or vista, when height support is added and we can have hills and mountains in the background.

This was implemented by re-purposing the commercial district type and giving it a negative gradient along it's radius instead of a positive one like the central districts.  I also parameterised the location, sizes and weights of the district types so we get much greater city layout variance as we vary the city seed values.

Some parameterised city examples

Demo Planning

I'm aiming to have my first-pass city demo-able by the end of the year, and so far I feel like I'm on track for that.  I thought I'd better make a clearer plan though so I spent a morning breaking down the things I have left to do and thinking about the timings.  Here's the to-do list:

• Finish filling out the placeholder zones (1) - I really need to fill in the residential and leisure areas as they will lend a 'more human' aspect to the city (business and industrial so far).  I'm postponing commercial and spaceport as there are more important things to focus on.
• Implement first-pass landscape support (1) - A big thing this city doesn't have yet is elevation.  It was always something I wanted to do to add richness and interest to the city.  So we need support for a height function (of some sort), blending (to interface with flat parts), and placing of blocks on landscape (giving them the appropriate elevation).
• Height integration (1) - Once supported, the natural areas (leisure, surround, and business in-fill) and the interfaces between adjacent elevations need content to provide pleasant and realistic transitions.  This will need to take into account block boundaries, height, and importantly; access ways (or lack thereof) between blocks.
• Detail pass (2) - Another pass is needed to add more detail to the low-level city, that you will see when 'walking around' at street-level. This includes features like doors, windows, pavement, as well as assets such as bins, streetlights, benches, planters, and maybe trees.
• Navigation/viewing (1) - To demo this city properly I need people to be able to control the camera in the standalone player.  This would start with basic is keyboard/mouse (FPS) support, with controller support coming later, and then maybe an attract-mode camera mode if there is time.  This would be quite involved as it will need to 'explore' the city to find good camera positions and paths (for some definition of 'good').
• Lighting (4) - I'd really like to try out my lighting ideas, they should really bring the city alive.  This would also include some fogging/haze/sky work, and maybe some simple clouds for fun.
• Bonus: Transparency and reflection - If I get time or want a break for something more adventurous I'll try and get some transparency and reflection support in to allow water and glass effects to be added.

Timings (in brackets) are estimated weeks.  We'll see how it goes as I am already a little behind and am still due to have some time off.

Next

I need to get the residential parts populated as soon as I can, so I'll be looking at more 'house-like' buildings and how to create them.

A realisation on progress

I've inadvertantly managed to make some progess, not physical progress, but psychological progress. A couple of nights ago I woke at 3am and spent the rest of the night mulling over some of the problems I face with this project. I decided to apply some very focussed thought to a single particular problem; that of synchronising data flowing between concurrent circuits (between threads of the same process, between processes on the same machine, and between machines via the network). It wasn't the progress I made on mapping out or solving the problem, it was the realisation that after writing it up yesterday that this was actually useful progress. It now seems an obvious thing to say, but this approach which seems to be along the 'divide and conquer' line may actually be the way forward.

I've tried this approach before, but I don't think I had the right framework in which to accomodate the results such that they would remain useful. Part of the problem has been how best to record my thoughts and expanding design; separate files, big word document, web pages, wiki, spreadsheets, one-note, visio diagrams, database, bespoke tools, etc. Having just tackled a very specific task I was looking for the best place to document it and realised it was really just the fleshing out of a small sub-section of the technical design overview. Not wanting to clutter the overview I rearranged the documents slightly so that this tech design doc acted as the to-do list and fill out another document with the details. This will form a technical implementation guide, some design, some solution, some thinking, and act as an execution plan for all the individual parts.

So, I didn't realise it, but my overview gives me a detailed enough skelton that can be fleshed out bit by bit and more-or-less at random. This means several things:
1. If I get stuck on (or bored) of part of the design I can switch to another.
2. I build up an implimentation guide to follow for when I actually write the code.
3. I am able to design a very large and complex system having broken it down into small parts.
4. I get to see really how large and complex a project this is (eek!).
5. It also breaks the deadlock with the hierarchy navigation UI problem I've been stuck on.

I guess none of this is new wisdom, but coming to the realisation myself is more potent than being taught it. Here's to progress!