10-12-2015, 11:56 PM
Hey! I'll try to help with your problem... it's so hard to try and explain this in text, I already wrote a post and deleted it since it seemed to not make sense!
You are fine with the freehand line G and how he projected it down to the ground to form line H (by dropping lines wherever G crossed any x-sections) ?
It's how he added the new x-sections to finish the curve at the very end to J that is causing problems right?
He has just added new x-sections, the very same way he did at the beginning by going down from the centre line to the ground plan, pulling it out to the side then joining the two points with a curved line - the confusing thing is that he didn't draw the full curve from the centre to the edge. He just drew up from the edge towards the centre line until it hits the freehand curved G, then he dropped straight down from there to plot the point on the ground plane. (look closely at the curving black lines going up from just before where J is marked on the step 7 image). He basically just mimicked the curve of the section line that was already there.
His process is very accurate and precise BUT it is still for artists and design sketches, not super pin point accurate stuff - so sometimes he will estimate a curve if the margin of error is really really small.
Let me know if that makes sense...
You are fine with the freehand line G and how he projected it down to the ground to form line H (by dropping lines wherever G crossed any x-sections) ?
It's how he added the new x-sections to finish the curve at the very end to J that is causing problems right?
He has just added new x-sections, the very same way he did at the beginning by going down from the centre line to the ground plan, pulling it out to the side then joining the two points with a curved line - the confusing thing is that he didn't draw the full curve from the centre to the edge. He just drew up from the edge towards the centre line until it hits the freehand curved G, then he dropped straight down from there to plot the point on the ground plane. (look closely at the curving black lines going up from just before where J is marked on the step 7 image). He basically just mimicked the curve of the section line that was already there.
His process is very accurate and precise BUT it is still for artists and design sketches, not super pin point accurate stuff - so sometimes he will estimate a curve if the margin of error is really really small.
Let me know if that makes sense...