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Intersection Ideas

Brendon Pywell

Bob's Track Builder
So one of the things I have planned is to address intersections; currently they are fiddly and take too much time. Whilst I have some ideas already (and made some progress), I'd like specific feedback from the experts here about how they would like to see the end result.

Ideally I'd like to give people as much control as possible, but also make it as easy as possible - there will always be some trade-off, but if you could have your way, how would you like to see the end result? What type of intersections would you find useful? How would you apply texture mapping? Would you want to use a specific texture (with textures already pre-merged) or have blending between textures from the roads that intersect (more costly on framerates and trickier for me to code)?

I'd especially like to here from those that are already achieving great looking results and good framerates and please do post screenshots to help explain your ideas!!

Thanks heaps!
In a mathematical sense, all intersections are a variation of Y-intersection. It just becomes a question of how many Ys you can stack on a node, right? The other half of the equation is how wide & what angle is each branch at the intersection? Final complication would be the inclination (or cross section) along the seam, particularly if both branches are banked turns with individual cross sections.

I think I prefer pre-merged textures to avoid (or better position) graining textures.
For many, Im sure they'll be wanting a simple 'snap' method of putting intersections together, but for myself & others, we'd like more control...
Personally, I'm with R Soul's idea of being able to swap the dirrection of the diagonal line in the road mesh, whether its possible to do it at a cross-section in the road or to copy the road & then select in the 'Track Choice' tab a left or right diagonal check box..
With the diagonal running in the opposite direction rejoining a pit lane (exit) on the right side of the track would be far neater...
Im not much of a texture (nor decoration) person so couldnt really answer that , I just think it would halp if we can at least get some tidy mesh-work laid down far easier...
Besides, I tend to try & use the same texture in both parts at a merging point.
Pics will follow as soon as I work out photobucket again...lol
Here's the first of my youtube tutorials on track merging:

The first one is easy because the diagonals line up with the main track. Almost everything can be done in BTB. Other programs are only needed to delete the overlapping triangles from the second track, and merge the vertices. If tracks could be converted to terrain, those triangles could be deleted in BTB, and if the main track was also converted to terrain, the vertices could be welded.

This one shows the complexity involved when the diagonals don't line up:
In this case deleting the overlapping triangles is harder. This video shows what extra steps are involved:
https://www.youtube.com/watch?v=84LMm_tXoi0 (UV mapping is mentioned in the next part).

When a track intersects at both ends, there will always be one end where the diagonals line up, and one where they don't.

I'm not sure how that could be done automatically in BTB, but an alternative occurs to me. What if BTB included special 'intersection' objects? E.g. this object is designed for 3d object programs, and ordinary roads can be built to line up with it. We could have Y or + shaped track objects with three or four nodes onto which a conventional track's nodes could be snapped.

I have a few ideas as to how they could be made but it's getting late and I don't have time to properly think about them.
i like the idea of y or plus shapes objected roads.maybe even a t-road too which can be flip on it x/y axis.

i made a quick [i mean quick] wire frame to show some pretentional problems with it thou. Eg mapping. and some verts needed to be adjusted to make it roughly a polygon.not a quad.
Has you can see by the first piccy. that the level of polys needs to be slightly different the width/ length. and in the second piccy the mapping has problem in the middle. has it was attached/bridge and collapsed together to make one solid road objected

i still a noob a 3ds maxs. so any experts many jump in.......... at anytime..... plz :D

apologizes for the long winded posted. and here the Hedex tablets. :rofl


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I pretty much exclusively make real world tracks, and as you can probably see I've made a fair few intersections using only BTB. I don't know much about the coding behind BTB so I can't say what would and be easy to implement and what wouldn't, but to me what is most important is that the process is completely controllable in terms of texture and shape. I personally can't see standard Y or T shapes working as no two track joins are ever the same, every track is different. Just look at the examples I posted. To me, that level of detail should be achievable without the many hours of editing that I put into them. And if the track is then modified later, it would be nice if the merged tracks could both move together (easier said than done?).

I would suggest the most effective way of doing things (if it is at all possible) would be to make cross sections more editable, for example the ability to add or remove cross section nodes at different points along the track would make things a lot easier, particularly on tracks where the grass edges and kerbs are also modeled in the track editor tool. If the nodes could then 'snap' the same way that tracks can when you press 'M', and then the unwanted vertices could be deleted perhaps?


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Just another thought, I don't know if others agree, but I have somewhere around 30 tracks within the current version of BTB, so I think it's also fairly important that these tracks can be edited in any new version.

Although I'm sure you've already thought of that and when a new version is released it will be fantastic as always.:)
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i never had problems with old tracks in new version of BTB. i just copied the old my projects over to new version of btb.

i think also you seem to have mis read my point of joining tracks. i would re-iterate a bit better.

the point of the post & pictures was to get Verts up out of the middle of the track which btb uses to more of the Edges of the btb track. has the current merge functions implements all tracks join in the middle. if the track Verts were more on the edges. we could have a bit more creative designs in btb,
like added extra sectons to the edge off track : EG runoffs,gravel pits. extra roads that go no where.a more of a proper pits area. instead of using terrain and having to change the shader to road all the time in 3dsimed,3dsmax.
You are right about the backwards compatibility in the past, it was just a thought that occurred but it's probably not an issue. I just thought that current track joins might be an issue, but then I remembered that I've been doing them without the help of any special merging tool, just the cross section editor!

Sorry but I don't really understand what you're trying to say with your other point. I was just saying that standard cross section objects (which was what R Soul was saying) might actually be detrimental to creativity.

The pictures you posted were actually describing something similar to what I was saying, with more edit-ability of the cross sections. But I dunno, I might be misunderstanding you.
One way to implement intersection is by making the end of the road angled in such way the user can control the angle. Now if you make an open ended road the road end is 90degree angled. If that angle could be adjusted from say 5 degrees to 90 degrees it might make it easier and less time consuming for pit entries and such.

Other thing that would be useful is to simply allow terrain to be connected to the end of the road. Now I think you can only have terrain connected to the sides of the road. This would allow terrain to be used to connect roads.

One thing that would be useful for these both solutions is some kind of snapping or aligning function that allows the two roads to be quickly and easily adjusted so that they are level and there are no holes between them.
Hopefully there will be a sollution. Till then i put some projects to a halt. The 3dsimed way does not work fully in my situation. (texture problems)