Lofting two rectangles

Dear fellow Rhino+Grasshopper users,

After years of drawing in Rhino I decided to pick up Grasshopper. It is a lot of fun but I still don’t fully grasp the program. Anyway, yesterday I made a little program to generate a tapered slab. I succesfully created a base curve for the slab (rectangle 0) and I want to loft it with the top curve of the slab (rectangle 1). However, I cannot connect the modules of rectangles 0 and 1 to the loft module. By which I mean: I can connect the module of rectangle 0 but but when I try to connect the module of rectangle 1, it breaks the connection with the first connected module. See pictures for more info. the GH-file and the 3dm are also included.

What am I doing wrong? Am I missing a piece of logic? Why won’t these modules connect to the loft module although the loft module can accept multiple inputs?

With kind regards,

Grasshopper_Eigen_Project_TabletmetRibbels.gh (8.5 KB)
Grasshopper_Eigen_Project_TabletmetRibbels.3dm (213.0 KB)

Grasshopper will not prevent you from making any connection, even if the data types on either end are not compatible. It will however erase all existing connections if you make a new one. To keep old connections, hold down Shift while making new ones. Also, if you hold Control and draw over an existing connection you will delete it.

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Agh! My bad! It is true - I forgot to hold shift (I saw it in your lesson too but I must have forgotten it.) Both modules now feed info to the loft component. I carefully fed rectangle 0 first, then 1 if that matters. Unfortunately, no Brep is created yet? Is my definition lacking somewhere?

Hard to tell without seeing it. However my guess is the rectangles were stored under different paths (one maybe under {0} and the other under {0;0}? Offset will do that). If you merge data from multiple sources, it will only put them in the same list if they share the same path.

The tooltip for the C input of the Loft component will tell you how your data is structured.

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Thank you David! I fixed it. The rectangles were indeed stored under different paths. I flattend the C-data in the Loft module and then it produced my tapered slab. I am very happy! Thank you for the tips David. I feel there is still a lot to learn, obviously, and that I still have to get the flow and intrinsic workings of GH but if I keep practising I’ll get there.

Until next time!

Hi, I don’t know if I need to start a new post, but I would like to know what is the best way to write the definition for what would most resemble the Slab command in Rhino or in VisualArq. I know that VisualArq has a component or a few for slabbing. but they haven’t released a stable version for V6, which is what I am using for various other advantages. I also would like to go through the mechanics of setting up the definition to learn better. I’m gonna take a stab at the definition, but unfortunately I cannot easily sketch my idea to scan and upload yet, so any tips would help. This is kinda the closest post I could find, but it seems outdated: http://make2d.blogspot.com/2011/09/making-slabs-with-grasshopper.html

Sounds like a different thread topic to me. Is this what you mean? You can make a cluster out of these components, perhaps substitute ‘Clipper’ for the standard Offset curve, which can fail sometimes.


slab.gh (6.5 KB)