Just a side question: Is there a way to move the arc on the left to a point of tangency with the arc on the right? Like is there a colored snap that will set in? (bear with my simple questions, this is my first time using SU)
It would be. An easy thing to do is to use metres instead of millimetres. Working at an enlarged scale removes the problem that Sketchup has in drawing small lengths or merging ânearlyâ the same points into one.
When finished, you can use the Scale tool to reduce it to the ârealâ size. Edges canât be created very small, but they can be shrunk without problem. If you need to edit the drawing afterwards, make it into a component, copy it and scale up the copy, work on the enlarged copy, and when done, delete the large one.
You may want to work with SketchUp set to meters as if they were mm. Only for your convenience to input equal figures and just to avoid problems where SketchUp canât create faces with very small edges ( <0.0254mm).
The units you choose are only used for displaying dimensions. They donât influence SketchUpâs accuracy.
You can scale down the end result by *0.001 to have the actual size in mm instead of in meters.
Agree ; I am amazed that we in in this forum will spend many man hours analyzing a post without asking the very first fundamental question: What is the pedigree of the provided data? This is a good example of that very case. It appears based on a standard rail spec ( UIC60) and there is / should be many internet link with info on that profile.?
It is your model so if you want to " dry lab" the model results that is your decision. I would still like to know what the ultimate goal / use of the model is??
It is generally accepted in this forum SU has problems with small size. I have not had that issue yet and the method used to make the model can contribute to that issue. The case in point is wherein Jim pointed out my results were not quite correct and he was correct. I used circles ( Su will show its estimated tangent points) to get the tangent points vs what is basically a tangent line (s). See his post above.
I cannot give a âbestâ scale factor to use .
The following is a some what better pic of the profile from https://www.alibaba.com/cache/UIC60-60E1-Rails-for-High-Speed_60549938185.html. When I went to this site for the link it is stated product is no loner available?
My plan is to create 2D profiles of several rail profiles (UIC60, BS113, some ARA standards I couldnât list off the top of my head). The end result is that I would scale and extrude these in Blender to create rail sections, but the reason Iâm using a more accurately-based modelling software Sketchup is to be able to get as much accuracy with my model as possible before I import it into a Blender file. I just wanted to ask for the techniques to model something like this accurately, and since I will be doing more profiles I need to know how to model those accurately aswell.
SU is a surface molder and as such it approximates curves with line segments with the vertices of the segments on the actual profile unles you use a Bezier curve. To avoid that artifact then you can: Use curves with a high segment count but that then makes the program large and the snapping to the desired vertices a potential problem. Model at larger size can help mitigate that: Use a vector base program.
Since you plan on using Blender SU should be usable to you. The test profile you posted IMHO can be done. The only spot where a intersection may be a problem is in the area you asked about moving the curves. The intersection of the 120R arc with the edge which is shown 19.5 mm off set from the 31.5+28.75 ref will give you the center point for the 35 mm line and you can check if it is done correctly in that it basically divides the 120 into 85+35 and the intersection of the two slopes at bottom on center line set the angle for the 35 and the 7 mm fillet.
Note the rail you posted has some symmetry and the you can just mirror to get other half.
Here again is the bottom section using only lines and arcs see if that comes close to meeting you requirements.
Also be aware in the total model sense that detail will be lost with buildings, train cars etc. ( You may have places where the rai will have to be bent?rail profile_2016.skp (232.5 KB)
You could make the rail a proxy say of just a rectangle. Than at a later stage the real rail can be used to replace the proxy.
Strictly speaking, SketchUp is a Face modeller. Faces are flat. Surface modellers use NURBS mathematics to define their surfaces that can be flat or curved, and use faces only for display purposes.
Anssi
For a more complete discussion âŚ
Iâm thinking that Sketchup uses Winged-Edge Meshes for data storage. Thinking about the speed of the inference engine all they need to do is determine where a ray passes through a face. Anyway - my 2 cents.
Some history for you:
Take two non coplanar lines, rotate one about end point and find intersection point with other. Easy ??
There are five possible solutions Su had a problem , see TIGs TrueTangent plugin
Make a 2d profile of the desired profile using edges, BUT with no radii at any of the corners.
Now use my 2Dtools Fillet toolâŚ
Select the two relevant edges with the desired radius typed inâŚ
It fillets those two edges at their corner as you wish.
If you are not a member of SketchUcation you can easily get a free membership⌠just read the guidance carefullyâŚ
