Graphical representation of axial forces compared with stresses....

[tony.ridley]

Mr Robot,

If I analyse a bar, the default colour for compression is blue, tension is yellow (on my Robot anyway).  

The default sign for tension in a bar is negative, positive for compression. This is backwards to most software i think but I can live with this.  

Then if I look at stress maps in panels it is reversed, so negative is compression.  

The "Cross" presentation then shows tensile regions as blue, compression crosses are yellow.  

I'm a bit confused now.  

Does blue always represent negative value of force / stress (tension for bars / compression for panels)? 

Same but opposite for yellow?

Can't we have a consistent set of values for tension or compression regardless of the analysis type (bar or panel)?

Cheers,

Tony

[Artur.Kosakowski · Accepted solution]

---

If I analyse a bar, the default colour for compression is blue, tension is yellow (on my Robot anyway).  

The default sign for tension in a bar is negative, positive for compression. This is backwards to most software i think but I can live with this.  

Then if I look at stress maps in panels it is reversed, so negative is compression.  

The "Cross" presentation then shows tensile regions as blue, compression crosses are yellow.  

I'm a bit confused now.  

Does blue always represent negative value of force / stress (tension for bars / compression for panels)? 

Same but opposite for yellow?

For default settings of colors it is true for bar diagrams and maps but it is as you noticed reversed for crosses. The reason is that the color of crosses is set together with the color of FX bar diagram and depends on the value (positive/negative) which is opposite for bars and surfaces. I agree with your suggestion that the color of crosses should correspond to maps and this suggestion will be treated as the proposal of having this changed in the next versions of Robot.

Can't we have a consistent set of values for tension or compression regardless of the analysis type (bar or panel)?

If you mean values then this would require tremendous amount of work (changes in all parts of Robot) and is not planned.

---