Inaccuracy when copying a step


#1

I have a stair, where I have copied four steps. The process is like this: I select the Component#31 - this is the step where female 01 stands on, under her left foot. Now I take the left corner (rear left corner in the top) of the copied component and I place it on the same point on the original step. Then I take Rotate tool and I rotate it using blue axis, so it should perfectly touch. The top side does not fit. I see 2.962mm difference. Why is it? The previous steps fit perfectly. I checked more times, compared with the previous step. But still not correct.

https://sourceforge.net/projects/autots/files/stairs%20pro%20patr%203%2C25%20skv_l_%20k_ivka%2C%20bezpe_n_%20to_it_%20schodi_t_%20m_rn_j__.skp/download

What I have found is that the same component does not have same length of the same edge. The difference is 0,2 mm. But the inaccuracy is ~4mm. Why?

width


#2

Several things are happening with this model. First it’s hard to be working on an architectural scale with .000 mm accuracy, Sketchups internal tolerance is about 0.025 mm. You can adjust the precision in Window>model info> units.

If you look closely at the intersections none of these steps line up “perfectly”. These individual stair units are all slightly different sizes. Although they are a component, they have all been individually scaled and skewed from outside their bounding boxes, which means these size changes are not shared between instances of the component. You can right click on any one and select reset skew and reset scale to return each to it’s un-adjusted state. If you want to make scale changes that will be reflected in every instance, you must open the component for editing and select all, then run scale.

Was this spiral stair downloaded from the web? I guess that because the individual adjustments to each stair seem to me to have ben an effort to make things fit together roughly.

Because the stairs spiral inward if every step is the same size the outside edge will continually march inward and not line up every time, this is just how the step is drawn, not quite right. In an effort to overcome this it looks like someone has individually adjusted every step after placement to make it fit.

The solution would be to start over with the first step un adjusted, make your first copy/rotate with step 2 and check the fit. You may need to edit the component to make that initial relationship fit. Then continue with the rest of the steps once component is made to fit correctly.


#3

Thanks. I downloaded. I scaled. I have modified the stair.

I make the component unique.


#4

I played with the step a bit more but it’s pretty damaged, lots of triangulated faces and out of square elements. For a perfect fit you would really need to start over and draw a fresh one. However by moving some lines around and modifying some faces I was able to cobble together a “pretty close” version that is repeatable. I did this by setting up two steps next to each other and banging the component with a large hammer until the ends sort of matched, well the digital equivalent. Take a look, perhaps this will help get you closer.

I backsaved to version 8 as this is what your profile indicated.

https://drive.google.com/open?id=1PQmS8Bd45KD02D6449Gv5snB_Nyj6Gyc


#5

I have corrected the step already. I made some intersections and edges removing to make the cuts laying in one plane.


#6

Great. Sometimes using models from the warehouse is more trouble than it’s worth eh? Glad you got it working.


#7

But it was an inspiration. Currently my problem is that I should fit to 18 steps being beared by one beam. I wanted to create ~ 26° stairs angle. But that leads to more steps than allowed in my country. I will spend yet some time with it to finish it.


#8

screw the code, be a rebel! :laughing:


#9

Bingo, I have fit to 16 steps using of 16cm height.


#10

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