Dual line component separation potential


Sometimes I think I’ve arrived on another planet… :thinking:


Perhaps you have o.O
Previous comment relates to curved surfacing issue i have been having, I have some T.D. knowledge but not programming language.


How would you describe a trapezoidal plane ?


Well, a plane is flat, like the earth used to be in ancient days. A trapezoid is a four edged flat shape, two opposite edges parallel, the other two connecting them.

Or are you referring to a flat trapezoidal wing of something similar to a wing of an aireplane?

@sWilliams uploaded a model with “blades” represented by two curves.

SketchUp is a surface modeler. You can connect the vertices of the two curves (stitching them together) with the ‘Line’ tool, thereby creating multiple triangles. These triangles will each support a face. The stitched lines can be made smooth and hidden to give the facetted surface between the two curves the appearance of a smooth surface.


I am talking about any shape of surface. A plane does not have to be flat. inflate deflate option is possible by what i have just described.
I was trying to create a cylinder within a tube with fan blade attachments and the auto surface did not work well.
I lost some of the surfaces of the tube, that I can no longer fill, by deleting erroneous surfaces that auto generated outside of the lines I had added.


Just an example:


looks nice but how do adjust elevation of curved edge ?
when creating a curve that fits a geometry that symbolises a curve there is more issue than describing a flat part.


As long as both sides (base and tip) are arcs you can manipilate the arcs by their cardinal points on the arcs. You can (for example) lift a corner to increase / decrease the curvation of the surface. So does moving the middle vertices of both arcs.
((Here I made the tip (front side) into collinear edges so the tip has lost its cardinal points.))

You can also scale one or both sides of the wing to make it more into a rectangular shape or sharper (say when looking at the wing in TOP).


Why don’t you just draw a few sketches that you upload as images, showing different shapes that you are after.


Ok I shall explain the complexity of what I am trying to create.
The curved edge i would like to follow a square root curve.
At an angle of outer points at 45degrees on the inside edge of a tube.
I want to do the equivalent of lifting the centre of your flat curve whilst maintaining the same vertical perspective of the curve on a different image.
I will however when this is possible go from the root curve on a cylinder to a flat that attaches at the inside of the outer tube.
The reason for parallel line was for tolerance settings but also for blade thickness.


Make this into a clear sketch with some notes (where to lift, change curvature, change angles etc.) Even use my image with notes on it, showing what is to be changed to… what.

A square root curve in SketchUp wouldn’t have any cardinal points but can still be scaled in various ways to manipulate the curve. It will drag (= deforme) the whole wing surface with it, taken that you maintain straight lines from the inner curve towards the outer curve (wing tip).


you want hand drawn or the failed attempt at a flat bladed fan that i have started ?
The version of sketchup I have is browser based and the file is not on my pc, I do not know how to share it with you but have it open in front of me.


A square root curve in SketchUp wouldn’t have any cardinal points but can still be scaled in various ways to manipulate the curve.It will drag (= deforme) the whole wing surface with it, taken that you maintain straight lines from the inner curve towards the outer curve (wing tip).
root curve is from a single perspective. I wish to mount that on part of a cylinders surface that is not round but a set geometry based.


square root graph example:

Wing shape derived from that graph: (just some manipulations)


You have good skills, I like the root curve.
What I want to achieve is having the root curve cross section attaching to the centre of a fan, That is a complex dual curve interplay.
Flatter part of curve at top of centre cylinder. Base tighter curve tip at base of cylinder, tip points at 45 degrees over height of centre cylinder.
There is more to the complete design but I don’t want to overload with info.
Centre of attachment radial, to centre of cylinder. Parallel tip points along blade edge to flat 45 degree attachment at outer tube or retainer ring that I hope to be a bearing.


The idea is for heatsink cooling fan.
Amongst other design relative projects I have in mind.
Heat sink will have root curve fins, tight in centre. Based on rotation speed of fan.
90 degrees orientation from vertical to flat relative to fan blade attachment for orientation of heatsink fins.


Help please. Can anyone out there “translate” the last two posts for me?

p.s. @alan50, you could do the translation yourself by sketching all your expectations/requirements per sentence in a few handdrawn images.


Where’s Wernher von Braun when we need him most?

So instead you operate with obfuscation?

And those who are trying to help you have to waste their valuable time trying to guess what you mean… which has basically been most folks on here.

Try a little respectfulness and go back and re-read the requests others have already made… and see if maybe you can respond to them.


ok first image of root curve on plane (grid) is lovely cross section.
from above its just a line right.
i want that line to sit 50/50 overhang either side of the radius of a circle.
the circle is in fact a cylinder
I then want to get the ends of the line seen from above to meet the circle.
circle must have diameter 1/3 larger than the length of line for four bladed fan.
the difficult bit here is the rotation of the curve / line to make tip to tip 45 degrees.
the height of the cylinder can be the length of the line/root curve.


Because the inside of a fan gives less down draft the curve becomes flat over the length of the blade for aerodynamic flow rate.

sorry sketch a bit quick and not well detailed just inside edge shown of bearing.
could put 8 of those blades to that and it would work well