Community
Civil 3D Forum
Welcome to Autodesk’s Civil 3D Forums. Share your knowledge, ask questions, and explore popular AutoCAD Civil 3D topics.
cancel
Showing results for 
Show  only  | Search instead for 
Did you mean: 

Math wizards question

26 REPLIES 26
Reply
Message 1 of 27
RobertEVs
1414 Views, 26 Replies

Math wizards question

How would you determine "X" and "Y" when you have a 1% slope or anything except 0%? 0 would be easy to determine.

 

2024-04-26_09-14-33.png

26 REPLIES 26
Message 21 of 27
fcernst
in reply to: fcernst

Jeff’s diagram shows the issue with Civil 3D where profiles, surfaces and corridors are not offset orthogonally to the profile….or a surface is not offset planar normal to the surface plane. The vertical offsets in Civil 3D are not relative to the object plane orientation.. just simply absolutely vertical. 

 

Joe and I interpret the original diagram as 90 degree angles with the triangle height always perpendicular to the base .. no matter the base absolute rotation. 



Fred Ernst, PE
C3D 2025
Ernst Engineering
www.ernstengineering.com
Message 22 of 27
Joe-Bouza
in reply to: RobertEVs

I see the effect that @RobertEVs  and @Jeff_M  are computing. but this raises another question. if the flow line slope is 2% then the upstream length become 9.1-feet and down stream become 5.9-feet which looks wrong, 

Joe Bouza
Did you find this post helpful? Feel free to Like this post.
Did your question get successfully answered? Then click on the ACCEPT SOLUTION button.

EESignature

Message 23 of 27
CahaLF7RX
in reply to: RobertEVs

Hello again,

Depending on what your standard curb height is.

For most projects I have worked on (for 33+ years) the standard has been 6-inches.

if the road vertical slope in not 0.0% (which is not practical for drainage), the ramp lengths will be different lengths (using the 1:12 max slope) or can be different slopes and the same length.  depends on who is sealing the drawing.

good luck,

nonbeard13

 

Message 24 of 27
fcernst
in reply to: Joe-Bouza

This discussion has digressed and permutated from the original diagram for isolating and computing x for completing the small triangles at a relative 7.5% within the small triangles workspace domain .. to an absolute 7.5% constraint now for civil grading work. There were no parameter caveats stating this in the original diagram. For example, it originally to appeared to be  a simple trick question.. that now the OP doesn’t realize he subsequently posited. 



Fred Ernst, PE
C3D 2025
Ernst Engineering
www.ernstengineering.com
Message 25 of 27
Joe-Bouza
in reply to: fcernst

I agree with you. I was only show the it impractical to use the flow line as a basis

Joe Bouza
Did you find this post helpful? Feel free to Like this post.
Did your question get successfully answered? Then click on the ACCEPT SOLUTION button.

EESignature

Message 26 of 27
teerawat.pSCHYQ
in reply to: Jeff_M

my understand that slope 7.5% are related with that 1%, and you talking about design profile for something. this is my idea about this,  if you create like a profile, and then add labeling for the tangent slope length, then you can get the correct slope length like this.  

teerawatpSCHYQ_1-1722314290644.png

 

 

Message 27 of 27
Joe-Bouza
in reply to: fcernst

I agree with you. I was only showing that it is impractical to use the flow line as a basis

Joe Bouza
Did you find this post helpful? Feel free to Like this post.
Did your question get successfully answered? Then click on the ACCEPT SOLUTION button.

EESignature

Can't find what you're looking for? Ask the community or share your knowledge.

Post to forums  

Rail Community


Autodesk Design & Make Report