How i can to extend NURBS curve or surface (in U or V direction) ? I can`t find this in SOP nodes..

Thanks

Perhaps its not what youre looking for but if you would do it manually you select the last or first point in the curveSOP and by shift+doubleclicking outside the curve re-enter the create state again and start adding points. Another way would be to add a new curve then merge it with the previous one and then use JoinSOP. Having persistent point display will also allow you to edit the joined curve as one without an additional edit SOP.

You can also try to calculate point normals and peak the last point along its normal. Here is a quick example.

Very true kuba. For surfaces I would probably carve out a curve that I extruded.

Wow, kuba and SoulVector, thanks you!
Nice and clean solutions I`m happy

~~~
i`n future, not now, i interested, create some solution for tangential extended curves and surfaces. I`t really helpful in some modeling cases.

I noticed the additional note about create a surface tangential to an existing surface.
Here are a couple of simple methods.

Probbins, thanks, but i`m sorry, i use wrong declaration above.
(my poor english.. )

When i say “tangential extended curves and surfaces”, i mean surfaces, or curves, created from other surfaces or curves, with tangential continuity…

I long times use Maya modeling tools, and now i use declarations from there. And (without “maya modeling”), tangential continuity and curvature continuity, is frequently used. Many kinds of fillets, many modeling tricks and workarounds can be created with it.

I think, this interesting task (but not needed for me right now). This will be interesting to solve this

Now you tell us what you are up to!

Look at the Join, Stitch and Fillet SOPs.

They work with both curves, surfaces or both combined.

Joint simply takes two curves or surfaces and makes one surface. c0, c1 or c2 continuity is moot but you can introduce breakpoints at the seam.

Stitch is what you are looking to if you want to get c0, c1 or c2 continuity between two curves, two surfaces or curves to surfaces. What's neat about this sop is that you can get tangential but not c0 or position continuity. Just enable the various toggles for position, tangential and curvature continuity.

Fillet introduces a third curve or surface between curves or surfaces.

There are other NURBs tools available. They are also mis-targeted. They really should have been called parametric tools… First, all these tools if they work on open or closed profiles (curves), then you can work on Polys, Bezier and NURBs curves. Parametric surfaces in Houdini are polygon Meshes, Bezier and NURBs patches.

You can also use the grid quite creatively to align to two or three points to create flat planes tangential to parts of surfaces to move CV's along.


-jeff

Also check the Project SOP, Trim SOP for curves on surface, Bridge SOP for building surfaces (fillets) between curves on surface.
Primitive SOP lets you transform a curve on surface (Profile SOP is also very useful for that).

Dragos

Thanks for advance in SOP-s, Jeff, this need, because i`m not understand sometimes, how Houdini NURBS work.
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and i don`t understand why i din`t see this two last posts. I don`t see any email notifications from forum about this posts:
by Jeff - “Posted: Thu Jun 26, 2008 12:50 pm ”
by digitallysane - “Posted: Thu Jun 26, 2008 1:09 pm”

digitallysane, sometimes i`m use NURBS SOP-s, but i have too many questions about it, and not have enough experience with NURBS modeling in houdini. i try to find Maya-NURBS-tools analog in Houdini, or create my own custom sets.

No problem.
Just ask away when you have questions.

Hello,

I'm trying to learn NURBS inside Houdini, but I do not understand a few basics things. What I'm trying to make is a simple rounded box from a box NURBS, but I can't manage to solve how the fillet SOP works.
The steeps I've follow are:

1_ Create a Box and change primitive type to NURBS
2_ Inside boxObject I've attached a Fillet SOP

I don't know if that is the workflow to build that object. Bellow I've attached a screen capture of the result.

Thanks in advance,

José

In Houdini, Fillet is used to generate a surface with tangency between the edges of 2 other surfaces. It doesn't generate trims nor does it creates surface between trims (you can use Bridge SOP for that).
It can also generate connecting curves between the ends of 2 curves (NURBS, Bezier or polygons).
The tool for your need is the Round SOP, it creates the rounding surfaces and also generates the trims.
Surfsect SOP is also useful for NURBS booleans.

Dragos

Thanks very much for the quick reply digitallysane. The Round SOP works perfect. I'm trying to learn all the NURBS SOPs but still a lot to do. One more question, do you know of advanced NURBS modeling videotutorials for Houdini?.

Thanks in advance,

José

I have no idea about tutorials on NURBS. there are tutorials on modelling in Houdini (CMIVFX and I think 3D Buzz), but I don't know how much they touch NURBS.

Dragos

Thanks again. I know CMIvfx and 3d buzz, but as far as i know they do not have any specific NURBS training for Houdini.

Cheers

A good way to learn might be to place each tool in the NURBS section of the tab menu and check its help. Most of them have example files which you can load directly from the help browser and can give you nice ideas for their use.

Dragos

Thats exactly what I'm doing just now :wink: . Thanks for your help, really appreciated.

i cann't find download files!