Up to Next Surface for Curves

Coreform Cubit Geometry
#1

Hello everyone,

I’d like to be able to create a line starting a a vertex, with a given direction and ending at a surface of unknown ID, (essentially I would like to know the distance along a direction from a point to a surface). In other CAD software I’ve used there is an up to next feature but I haven’t been able to figure out if there is such a thing in cubit (I understand cubit is primarily for meshing, so not a big deal). I figured I would check before hacking something together with the python interface.

Thanks,

Edgar

#2

Hi @Edgar21,
this sounds like you need the command

measure between {entity <id>|location <options>|plane <options>|axis <options> }
     with {entity <id>|location <options>|plane <options>|axis <options> }

https://coreform.com/cubit_help/cubithelp.htm#t=geometry%2Fmeasuring_btw_entities.htm

Here is a short example.

#!cubit
reset
create vertex location -1 -1 -1
create surface circle radius 1 xplane
measure between vertex 1 surface 1

grafik
grafik794×755 16.4 KB

#3

Thanks for the response, unfortunately I don’t know the surface I want to measure too, I have a point, and a direction in which there is a surface, but I don’t have a priori information as to which surface (100s to thousands of surfaces in my model) will be in that direction, if that makes sense.

I am thinking of just making the line extremely long and determining which surface it intersects, then making a vertex at that crossing and measuring between the starting vertex the vertex where the line crosses the surface, but I would like to avoid iterating through all the surfaces in my model to find the one that is along the direction vector starting at the initial point.

#4

Hi Edgar,

You might be able to do this by using the create curve <location> <location> command where the second location is specified using the fire ray``` location option. The command syntax is complex, but it works.

For example,

reset
brick x 10
vol 1 move x 10 y 5
create curve location 0 0 0 location fire ray location 0 0 0 direction 1 1 0 at surface all maximum hits 1

The first location 0 0 0 specifies the start point. The end point is specified by a ray with the start location 0 0 0 a direction vector 1 1 0 and an ending surface. In this case, I searched all surfaces but I’m only selecting the first intersection by using the maximum hits 1 option.

There is an additional option on fire ray, ray radius <value>, that can be used to tweak the tolerance for intersection calculations. The documentation indicates that this is required for curve intersections.

Here is a link to the documentation (it should point directly to fire ray), Coreform Cubit 2024.3 User Documentation

Does that look like a solution to your problem?
Karl

1 Like
#5

Yes it does! Thats awesome that theres a ray fire command, thanks for the help!