Technical display errors with blocks

Technical display doesn’t calculate blocks properly so I have to explode them for edges to be calculated. (It calculates everything as hidden lines)

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At first I thought you were reporting this as a Rhino for Mac specific problem…but now I think you’re reporting a Rhino 5 problem. Here are blocks on Rhino 5 for Windows:

and the same file in Rhino 5 for Mac:

Both look to be exhibiting the incorrect behavior you are reporting. Or am I misunderstanding?

Well, they both look bad…
But here V5 for Windows works fine.
V5 SR11 64 bit:

Quite a few blocks in the illustration I am working on:

It does mess up some edges on extruison object boxes though…
so that can be a link.

Logged in MR-2029 on the Rhino for Mac side. @jeff may want to take a look before he investigates the Rhino for Windows behavior.

When there are issues with blocks, it most likely has to do with intersection lines… So make sure that when you’re comparing the two different platforms, that all Technical settings are exactly the same.

That being said… Please remember that “Technical” display modes are just a bunch of display tricks using the depth buffer… If you see things that look like “hidden lines” that shouldn’t be, it does not mean that other features are somehow being treated has hidden lines… It means that those other features are either turned off or are not overwriting the hidden lines… Let me explain… Hidden lines are done simply by drawing all lines as “dotted” first, then the render meshes are drawn “invisible” thereby filling the appropriate depth buffer locations…then the solid lines are drawn… So when everything is said and done, the dotted lines that appear in the “foreground” should get overwritten by solid lines, and the ones in the background are untouched because they lie behind a populated depth buffer value…

This means that if your hidden lines setting is thicker than your solid line setting, you will most likely still see a dotted effect. It’s always a good idea to make your solid line settings at least 2 pixels larger than your hidden line setting… That might not be desirable, or even acceptable…but that is the reality of the situation and that is how Technical display in Rhino works.

The block issues can be numerous… The technical info used to draw the scene is pre-calculated in order to give you better performance. However, things like silhouettes obviously need to be recalculated on every frame. With blocks, there is really only one set of geometry to work with, which means all pre-calculated values are getting done on just that one block definition (i.e. not the reference)…Why? because at the time of the writing, you couldn’t store information on the block reference, so I needed to come up with a way to transform the technical information just like the geometry in the block the definition when drawing it…That mostly works…but sometimes does not… and I have no idea why it doesn’t work in some cases but does in others.

Hopefully V6 will give Technical capabilities a complete overhaul and doing things better, and more correctly and accurate (i.e. Eliminate many of the “tricks” being used to achieve the same results).


Thanks for the info Jeff. Just for the record, the problem is on the Mac and not the windows version.
I’ll fire up the mac and get you some screenshots and an examplefile too in an hour or two so you can see for your self. It works fine on the PC. (But extrusion objects are faulty on both.) The “Pen” display mode is the factory defauld exept I altered the background to solid white. And it works fine if I select all blocks and ExplodeBlock.

Sorry for the delay, here are the ccreencaptures:

PEN display mode with a clipping plane shows that blocks are not calculated correctly:

SellBlock to show blocks before running ExplodeBlock.

(I have NO idea why the yellow selection turns up blue on the ViewCaptureToFile)

After ExplodeBlock is ran all is good:

Saw same with imported data that came in as blocks - in pen mode the blocks did not display anything until fully exploded. Elements displayed fine after being rejoined into poly surfaces too.

Related to blocks - the import created a huge number of block elements. In block manager could not fine a method to either select multiple blocks for deletion or delete all. Had to delete each block element one at a time using the little menu drop down. Major hassle! Delete key does not work either. At least it would have speed the process.

Am I missing a better way to delete block elements other than one-by-one using the little drop down?

Type SelBlock to select all blocks.
Type ExplodeBlock to explode all blocks and sub blocks.
Then type purge to clean out all blockdefinitions.

Hope that helps


Simple, Sweet, Works…

Love it, THANKS!

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