Hello. Absolute beginner question, I apologize, but I simply don't get it. How is it possible in Houdini to draw splines with curves AND corners? As far as I can see I can choose between polygon mode (just corners) or nurbs and bezier (just curves). But I need to combine both in a single spline to be able to draw what I want.

I seem to recall that Bezier curves in Houdini can represent multiple connected Bezier curves, so if you have an order-4 (cubic) Bezier curve, vertices 3, 6, 9, 12, 15, … (where the first vertex is 0), can be corners if it, the vertex before, and the vertex after aren't all in a straight line.

For a subdivision curve (like a subdivision surface, but for polygon curves) or an order-4 (cubic) NURBS curve, you can also do it by repeating the same point position 3 times to make a corner. You can turn on viewport display of polygons as subdivision surfaces/curves by pressing +(it might or might not need the Shift key) and turn it off by pressing -. There are separate options at the object level for subdivision surfaces and curves in Mantra.

Hopefully that's what you were looking for.

nigromontanus
Hello. Absolute beginner question, I apologize, but I simply don't get it. How is it possible in Houdini to draw splines with curves AND corners? As far as I can see I can choose between polygon mode (just corners) or nurbs and bezier (just curves). But I need to combine both in a single spline to be able to draw what I want.

You can't. It will hopefully come in H17 next year.

just use bezier curves, they work exactly like bezier curves in other softwares, just with a limitation that you don't see the tangents and they are untied all the time, but if you imagine the tangents, you can make any shape you want

tamte
that you don't see the tangent

just turn on primitive hulls

Yes, working with NURBS curves and creating multiple points for corners works. Although it's not very elegant and I'm not sure if this workflow creates problems when modifying or editing the spline at a later stage.

@tamte: Yes, bezier curves also work somehow, if I get used to the fact that there's an automatic corner every third or fourth point.

Thanks for your help! But I also agree with aRTye: it's a bit strange that a sophisticated software like Houdini doesn't offer a straight, user-friendly solution for such a simple task.

Bezier curves are what you want. But as what Tamte said above the bezier spline editing controls are not very sophisticated as you would find in Illustrator where you can tie and untie tangents on edit points and more.

Please submit an RFE.


One way to approach drawing spline type curves quickly is to draw multiple curves with point snapping on.
- Set up the viewport Tool Option button menu set to “Create in Context”. Thats the tiny button on the top viewport toolbar right hand side just left of the ? help button.
- Once that is set, you can dive in to an object and tab type Curve once and draw your first NURBs curve.
- Hit “Q” to repeat curve when you want a sharp corner and continue on drawing the next NURBs curve with point snapping on to start from the previous point.

Then use a Join SOP after merging the curves together with Multiplicity on.
You can then convert to polygons without duplicate points on the corners.