Loft Tool Not Creating Planar Faces

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#1

I wanted a Pyramid type body; however on my base sketch only two sides were equal. Let’s say the equal sides are 5 in. And the other two sides are 2 and 4 in. First I tried the Extrude tool with draft but this will not come to anything like a sharp point at the top.

So I lofted the base to a small square above the center of the base. This worked and it looked good. Shelled it out. But I could work only on 2 of the 4 faces of the shape. Did an inset and push to remove the triangles. When I tried to sketch on the other 2, error message. Sketching can only be done on plane faces. But I can select the 4 edges and it seems to be a planar face?

s3d file encl.Stand Base.shapr (804 KB)

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In retrospect, perhaps I should have made my tiny top face with the same proportions as the Base shape and all would be fine? Is this a condition to have lofts with all faces planar? I will do a simple minded experiment to try to understand this better. Thanks

#2

I did a simple test to see how this works…

imageimageimage

Unfortunately I cannot draw on any of the faces? Although s3d seems to consider them faces. The base rectangle and top rectangle are of the same proportions with centers positioned exactly above each other.

Am I unclear on something or is there some trick to this? Thanks,

Tommy

s3d file encl

Loft Test.shapr (404 KB)

#3

This is an interesting observation, in this case loft should indeed simplify the geometry to get planar faces. We will look into this, thanks.

#4

My goal is to create a model inspired by this knife holder. The shape in question 2 posts up is like the left end shape in the picture (needs to be rotated 90 deg up and left). Have been experimenting with various approaches.

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This must have been designed with a solid modeler so I keep on trying.

People are also 3D Printing PolyThinker so here is another modeling challenge for someone.

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To learn, I am modeling existent objects but I would like to model: mind to screen.

Thanks,

Tommy

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#5

A bit more on this. You can do a loft that will always result in planar faces with the following technique. Draw 4 line base sketch. Pull base up to create a shape. Inset top face as much as possible such that smallest edge still exists. Delete shape; loft between sketches. You can draw on four planar sides (I did circles).

But this does not solve my problem as I want my polyshape to be pointed. The ideal would be the ability to loft to a point on a plane. That would get result in a pointed polyshape. Any suggestions on how to accomplish would be appreciated. Thanks

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#6

I guess that the request is for a Tool to loft a polygon to a point. With the triangles created that are all faces. This would make it easy to create a polyshape.

This is a bit similar to the Cone tutorial where a circle is extruded to a cone.

Thanks,

Tommy

#7

It would be less convenient, but can’t you intersect two triangular bodies to form your shape? Create a cube with the outer dimensions you want & sketch the projection on the respective sides. Extrude two or three “Toblerone bars” & intersect.

#8

This is a great suggestion! Will try it… Thanks
Tommy

#9

deets’ suggestion did the trick. Oddly enough though, I would get an error message - invalid shape - when trying to Push away the last section of the cube. So I translated a Copy and the Push worked on this - success!

In retrospect I was looking for a solution and was thinking along a 2D direction instead of a 3D one.

Thanks again,

Tommy

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#10

The killer tool for this type of construction would be Loft Polygon to Point. Just sayin…

Thanks,

Tommy