Tunnel Slope Problem

the real simple answer: you need to make the corners square instead of diagonal. in your top-down view, the corners are 45 degrees. if you make the corners square instead, then you can leave the ends of the tunnel straight, and ramp the middle.

you cant have too many angles at once on one brush. brushes need to be convex solids, which generally means they have to have planar faces. if a 4-point polygon has verts at funny angles, its not a flat plane anymore, and it'll screw up your solid shape.

re-make the tunnel so the ends are straight like you want them, they go in, and then open on the sides toward the sloped section. if the sloped section is square from the top down, then you're only angling it on one axis, and your shapes will be fine.

of course this requires some re-thinking of the displacements.

Why don't you just add four brushes around each tunnel exit, to fill the red squares?

Your displacement faces should look like this:


For best results.

You should lay out your brushes, prior to displacements, like the right side of my picture, rather than the left side (which you have now). Then you can take the center section and ramp it (I would do that prior to making all of the brushes displacements).

Well then i'm not really quite sure what you are trying to achieve. TDSOYS's basically reitterated what i said, though only because i slipped my post in between him loading the page and replying (probably). Doing your egdes like that wont make a difference to your displacements, it just makes it look neater in your wireframe views.

This is what i got (and i actually liked how it turned out regardless of the fact that i hate the subdivide tool).







To achieve the same effect on the outside you will want to repeat this but inverted. Assuming you manage to allign all your faces you shouldn't get spikes or "squarey" appearences.

Here:

(try and ignore the position of the brushes in the 2d views untill the last stage, as i forgot to allign 2 faces on the bottom and top. and had to go back and fix it).


Having produced your inside you will need to create an outer shell. The process is the same, though more attention to allignment is critical. You will need to change the block sizes, basically increasing their size untill all their egdes meet. Special attention to the inner allignments such as inside corners is a good idea, as these 'blocks' on the ends will actually have to be reduced towards the "hole" ends.


Note in the 3d view how they overlap. Ignore the 2d views, the allignment is wrong.
see link.


Note the slight difference in angles on the slope due to the allignment changes, this shouldn't pose a problem however, but to be sure, give yourself some space. The space here is merely the width of the blocks i have used, from the inside - to the outside, as the original brushes possess the same space as these new ones.


Assuming nothing went wrong your outter displacement should look like this. If you find you have spikes, or square corners, 'destroy' the displacements and check for mis-allignments. Then re-subdivide.


Your final product. (i had the inner tunnel hid in a manual visgroup so that i could see what i was doing, and turned it on at the end).