# Subdividing Surface On 2 Sides Of A Box - U & V in opposite directions?

Hi All,

I’m a beginner to GH so there may be a much better solution for doing what I am trying to do, ill give some context at the end after I’ve stated the issue at hand. I’m trying to use the ‘iso trim’ component to subdivide the bottom and top planes of this box - I want both to be divided the way it is on top - 3 x 5 - but this is reversed at the bottom? can anyone tell me why this is? I’ve attached the definition.

Cassette Generator V2.gh (27.1 KB)

Also, im ultimately dividing the surfaces of this box so i can offset the edges of each section around the perimeter to add some notches - see the other screen shot from an earlier definition in which I went about it using ‘list item’ to filter out every individual edge - again, probably not the most efficient way but it worked and now im trying to get to that using less components. any advice would be appreciated.

Hey Dan,

For comparison, if you think of a square, the two edges on opposite sides will have opposing directions - you will see a similar thing if you look at the points that make up the individual faces of your box with something like Point List - one solution you may consider is to generate the desired pattern on one face and then project the curves to the opposite face.

Depending on how you construct your box, you face U & V domains and directions may change (try Domain Box or Extruding a curve etc. to see how your uv directions move.)

The simplest thing to me seems that you measure the two pairs of edges and construct lines between them instead of relying on rhino to correctly assign uv directions. Well there’s quite a few workarounds really (Offset the edges inwards to help with generating your joints, create boxes where you want to add or remove material etc. etc.)

Hope that helps a bit,

Sash

Hi Sash

Thanks for the response. In regards to your first solution, what’s the best way to transfer that pattern of curves from the top plane to the bottom plane of the box?

I have tried offsetting the edges which works great. but the edges on top of the box offset inwards at -18 like they should, whilst the edges at the bottom of the box offset outwards even though -18 is put into the direction input on ‘offset curve’. Again this may be something to do with the UV directions.

I’ll keep working on it and try out the suggested solutions.

I have no idea what “notch” means anyway, IMHO, you could set up the whole process differently from the first place instead of using Isotrimover an exploded box…

Cassette Generator V2_re.gh (12.6 KB)

Hi HS_Kim,

When I say notch I think the correct terminology to describe what I’m trying to do is create a box that consists of 6 individual sides, all 18mm thick with ‘finger joints’ (larger notches) that scales depending on the size of the box. i.e if the box is over 1500mm high the sides are divided into 7 resulting in 3 notches. if it goes under 1500mm it divides into 5 (2 notches). these sides are then baked into rhino separately.

Thanks for taking the time to create that definition, I’ll study it and see how it works. it looks like it has potential.

Hey Dan,

For simple geometry like a box you could literally use Project to Brep (you’ll see there is a project to plane and project to brep in Gh) - you could use the negative normal of the face to project the curves (DeconBrep>EvaluateSurface) (If the faces are the identical you could even use Orient)

The offset inputs include a Plane input, again deconstruct your faces and evaluate the surface to get Frames (Planes based on a geometry), use these frames as the offset plane to have all the faces behave in the same way - hope this helps. (You can usually Flip the curve as well if your offset is going the wrong way as well)

Sash