Why is my spline not extruding the way I want it to?
polycounter lvl 9
For the inner portion of the sprocket I Booleaned a custom spline to a circle, but it won't extrude that portion. Is it because of the custom spline I Booleaned? I figure it might be because the default shapes like circle, square, star, etc all me to extrude upon using Boolean.
The middle and far right shape are extruded, but as you can see it will only extrude the outer ring.
Am I in the ballpark?
The middle and far right shape are extruded, but as you can see it will only extrude the outer ring.
Am I in the ballpark?
Replies
You could try... going back to the splines, attach one to the other, create some cross sections and apply the surface modifier.
Or you could try... detaching the inner spline so its a separate object, convert both to edit poly, then ProBoolean the inner shape to cut out of the outer shape.
Booleans only effect shapes and geometry that is overlapping, if there isn't any overlap then there is nothing to Boolean, especially with a spline. So you have to convert it to geometry and then boolean.
As it turns out the custom spline shape, like you were saying Mark, won't simply extrude like it would if it were a default shape like a circle or square and customized from there. This is with the same outer rim, but the inner circle is Booleaned with a square later customized.
The inner spline probably isn't closed so you should find the 1st vert (yellow vert) and make sure the last vert is welded to it. Then make sure there aren't any breaks anywhere else, select spline and click on a line, the entire thing should highlight, if it doesn't you have a broken line and you should weld it. The final check is that you can select on any vert and click on "make first" and it changes.
IF all that fails to work, and sometimes it does... turn on 3D snaps, turn on vertex snap, and create a new line by clicking on each vert in the spline and making sure that when you're all done to click yes to the "close spline" message box at the end.
Jack - I tried converting it but a spline can't be turned into an editable poly unless it has faces of some kind. Any way I go about doing that is pretty much gonna give me a cookie cutter like shape with the cap.
Try weld it all up, then split a new vert and make that the first knot, then weld up the old gap. I think sometimes Max just gets confused with the end knot position and then fails to extrude.
In your first picture any way, shouldn't the centre not be filled? If you select your outlines and extrude to 0 it should leave an empty space. That 'leaking' is a sure sign Max doesn't know that the gap between the two spline shapes should be air-tight.
Another check is scale to 0 in the z axis (up/down) to make sure it's totally flat too, then perhaps a reset x-form if you've been scaling.
Or re-draw over the top if all else fails, snapping in 2d with the new spline objects.
Dave
1) The outer spline is a bit messy, some of the outer teeth on the sprocket have double verts which is going to cause problems.
2) You need a plan for the edges connecting the two pieces together.
3) Centering the pivot point should help you align, rotate and duplicate pieces so they are mathematically correct and in the same spot, being off by a little will create funky geometry and will only complicate Boolean operations. Booleans can be very messy even when fed very clean geometry.
To adjust the pivot point go to the hierarchy tab, turn on effect pivot only and click "center to object". This will make aligning two circles much easier, you can just snap one to the other.
4) In the file you sent, if you go to vert mode, select all and weld with a setting of 10, it will extrude properly. But because the geometry was not as precise as it should have been, there is a lot of clean up that needs to be done...
You can see that the teeth aren't the same, some are really dense and others are low poly and the inner cylinder has a crazy uneven number of sides as well as messy geometry... this is bad...
I suggest starting over and work around one central pivot point and be sure to use exact angles, turning on angle snap will help with this. Honestly I would skip splines and just build this out of geometry.
Here is how:
Step 1) Create 2 cylinders one big (360 radius, 32 sides, height 32) and one smaller cylinder (45 radius, 8 sides, height 90).
Step 2) use the align tool on the smaller and align it to the larger cylinder, then move it up on one axis, so that half of the cylinder is floating above the larger cylinder, this should help control the number of verts created when you Boolean.
Step 3) Squash the cutting cylinder a bit in Edit poly.
Step 4) Go to the hierarchy tab, turn on effect pivot and align it to the larger cylinder. This will move just the pivot to match the larger cylinder.
Step 5) Hold Shift (to clone) and rotate the smaller cylinder 10 degrees (angle snap helps with this), make 35 copies.
Step 6) Select all of the smaller cylinders, right click the viewport and choose isolate selection, convert it to edit poly, attach all of the other cylinder to it, un-isolate selection.
Step 7) Boolean and clean and get ready to boolean some more.
Wash rinse repeat for other pieces using the same tricks to keep things as exact and as clean as possible.
Also don't forget about the symmetry modifier and your ability to rotate the symmetry mirror gizmo, it can help with some operations also.
You can use "create" while in edge mode of edit poly, to define new visible edges and the hidden edges will recalculate.
If you use cut you run the risk of accidentally adding geometry by clicking near a vert instead of on it. With cut you have to be hyper vigilant about watching the mouse cursor and making sure it really is right over the vert. With "Create" it can never accidentally cut the geometry, it only strings a visible edge between two valid verts.
But that is a lot of work so here is what I would do.
1) Define the ends of all the teeth using "create" (Edit poly, Edge mode), its a bit of work but it simplifies things for the next step if you don't have to deal with the teeth.
2) Delete the inner poly (leaving the teeth intact).
3) Go to boarder mode, select both boarders, then click the box next to bridge to bring up the bridge tools. In there use the two "twists" that you can use to adjust the angle of the edges and hopefully avoid what you had a few posts ago, but really defining the teeth will help with that a lot more.
OR
You can also toss a "turn to poly" modifier on top of your stack and set the number of sides to 4. Then go back down to edit poly, edge mode and use "create" to start defining edges which will force the hidden edges to re-triangulate. It's a bit of a gamble but you might not have to define all of the edges.
It can be a bit crazy to work like that, so toggle on and off show end result or the "turn to poly" modifier (little light bulb).