how to make a circle with spline.

Development Programming & Scripting
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1

hi,find that the length of tangent line affects the spline curve.


I tried to adjust it manually ,but it’s hard to get what I want.I want to make a perfect circle.i guess the tangent length might relate to its radius,anyone know how to calculate it?

2

Hi,I finally found that the circle radius * 1.65 = the tangent length.but I don’t know why it’s 1.65.

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3

If you’re doing this within a reusable blueprint actor, then you can use math within the construction script to create this for you, with customizable parameters. There was a previous thread on this topic with some really helpful examples:

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4

thanks,very useful information.collection+1.but the post says radius*1.5 for the tangent.i think that is not round enough.it’s 1.65.

5

After hours of researching.i kind of forgot why I needed this …

6

Yeah, a respondent in the thread (MarGon) pointed that out further down and gave the correct mathematical formula for that constant:

k = 4 * tan(angle / 4). For 90° it will be k = 4 * tan(pi / 8) = 1.6568542494923801

So, the precise value you’re looking for would be 1.6568542494923801… rounded to whatever decimal accuracy you’re going for. (1.65, 1.66, 1.657…)

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