Clipping plane needs a fix!
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I've been having serious issues with the clipping plane and it's driving me nuts. I know the clipping plane issue is a common complaint, but I've been looking into it.
I was told by Sketchup support that the biggest issue with the clipping plane is that when geometry in the model is too far away from the origin, it affects how much memory OpenGL is using. This makes sense, considering OpenGL has a depth buffer that needs to be set. You have a far and near clipping plane, and everything in between is buffered. I assume that Sketchup dynamically adjusts the far clipping plane based on what object is the furthest out from the origin.
I was told to put geometry onto layers that can be turned off for when they are behind the camera, and this will help with the problem. Makes sense.
However, it appears that Sketchup has something configured wrong for the depth buffer. I've been running multiple scenarios to figure out how to work with the clipping plane issues, and here's what I'm seeing.
Starting with a blank model and creating a 100 foot x 100 foot box, then setting the camera FOV to 60 or above.
Draw a box 60,000 feet away on the GREEN axis, and another that's 60,000 feet away the other direction on the same green axis. The clipping issue doesn't happen.
Now do the same thing, but draw them on the red axis (keeping the other boxes on the green axis). Clipping issues are now noticeable (larger buffer area, I get it).
Now put the boxes that are far away from the origin into their own layer. Turn off that layer. The clipping issues are still noticeable.
It appears that Sketchup is still using a depth buffer for the objects that aren't even visible. The only way to correct the issue is to physically erase the objects. Hiding the objects doesn't solve the issue either. The moment the objects are erased, the clipping plane fixes itself.
It would be nice to have a dynamic clipping plane that can be adjusted by the user. I brought my model into Blender just for the heck of it, and the clipping plane issue is nonexistent. The way Sketchup handles the clipping plane seems wonky, and having manual control over the near and far planes would solve most, if not all, of my issues.
I wonder if the zNear setting for the clipping plane in Sketchup is set too close to 0. This can cause issues like this, but if the planes were adjustable, it could be quickly determined.
Please, Sketchup dudes, fix this for the sake of my sanity
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Of course it would be good if the clipping-plane issue were properly addressed...
But you make a rod for your own back by working at enormous dimensions.
SketchUp was designed to work on 'building sized objects', so it goes down to furniture, even ironmongery - but not parts of wristwatches - and up through windows/doors, roofs, to buildings, sites and even city blocks - but not whole cities or counties...So if you model to those large sizes the clipping plane is currently to be expected.
Other reasons you get the clipping plane are:-
That geometry is unnecessarily far from the origin, if so move it nearer.
One cause of this is importing CAD plans and keeping their origin, which can be miles away fro [0,0,0].Some rogue geometry fragments or guide-points etc is miles from the origin - either in the model or inside a component or group.
A component looks like it's near the model's origin but its geometry is miles from the component's origin.
One cause of this is that imported CAD blocks that become components can have their origin at some 'world-origin', miles away.A component looks OK but it's been scaled.
A cause of this is that a CAD user has imported a block - say a door - that was originally drawn in mm into a m DWG, instead of scaling the block's contents they scale the instance of it and copy that.
Now the component definition thinks it's 1000x bigger that it ought to be... Thus the model's bounds are potentially x1000, so a 50m city block is actually a potential 50km !You speak of "putting geometry on layers" - I hope you misspoke.
All basic geometry [edges/faces] belongs on Layer0.
That geometry is then assembled into Groups or Components which are assigned other layer as desired.
Those layers control the visibility of those 'container' objects in SketchUp.
However, the model's OpenGL bounds relate to all of the model's contents, irrespective of its objects being visible... So layers are not useful for reducing a model's effective 'bounds'.Have you looked at what might be making your model's bounds so large ?
If it's just an enormous model just are stuffed.
But if you can fix issues like the origin location, or badly made block-components these will ease the pain... -
Hearing that I bought a program that can't do what I needed is very unsettling. I don't understand why a free program like Blender is able to view my model from Sketchup without any clipping issues at all. It uses OpenGL and has full clipping plane control. Considering Blender is open source, can't someone from Sketchup see how they designed their camera controls and follow suit?
If Sketchup is simply not a solution for what I need, nor will it ever be, then that really sucks.
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your written example appears to be such an uncommon prerequisite, can you post an 'real' example skp with the issue, there may be a simple solution to your particular issues...
SU already has full clipping plane control when you use 'Section Planes', it's feasible that this feature could be hindered by allowing user adjustment of the base settings...
john -
I'm working on a 3 mile section (5.23 km) of roadway with trees, buildings, cars, road striping, etc.
Sketchup is handling the model itself beautifully. The one and only problem is the clipping plane. I need to do a flythrough at the eye level of a vehicle that follows the roadway. However, only the top 1/3rd of the screen shows the model as the rest is clipped off. If I could lock my clipping planes to a few thousand feet view distance then I'd be set since that would probably fix it.
EDIT: Your comment about section planes made me try an experiment and clip a segment that's only 500 feet in length. Nothing else is visible. It still has massive viewport clipping problems.
Even with geometry being clipped out with section planes, it doesn't have any effect whatsoever.
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have you tried using an 'Advanced Camera' with a fixed aspect ratio, fov and focal length and 'View thru camera'?
just a thought...
john -
Yeah, I messed around with a bunch of advanced camera settings, but if anything, it just makes it worse. Real bummer.
Something else that's very interesting is that adjusting shadows will tweak the clipping plane on the fly. If I adjust the time of day, you can see the clipping plane move in and out from the objects in view.
Weird.
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from my understanding, 60 degrees fov requires an extreme aspect ratio to avoid OpenGL clipping...
http://ogldev.atspace.co.uk/www/tutorial12/tutorial12.htmlif you shorten you SU window, does the clipping improve?
i.e. try 3:1 aspect ratio of the actual window...
if your on a mac I have a plugin that makes that easier to do...
john -
Yep, I've tried messing with aspect ratio, screen size, shadows, resolution, advanced graphics card overrides, etc. without any luck whatsoever.
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Hello,
I've been using Sketchup from the beginning, have never really had clipping plane issues in the past that were much of a bother until recently. Working on a model that is relatively small compared to some I've constructed and I can't get close enough to objects while editing...for example a 1/2" dia. bolt. This is driving me insane to be honest and I have exhausted my options. I've opened a fresh new drawing, no issues editing something small. I've tried turning off layers, deleting everything around what I'm trying to edit...no luck. I can zoom in fairly close to an object (not great, but close enough to edit) as soon as I right click on edit group or component it disappears from view....I saved it as a sketchup 8 file and tried it there...same results. I'm sure it's something simple that I have overlooked.....Help would be greatly appreciated.
Thanks -
The only way to fix the clipping issue is to zoom way out and then switch to parallel projection for your camera. Now you'll be able to zoom back in without clipping. Turning off layers/hiding objects has zero effect on the clipping plane issue. The only way to fix it is to completely remove all objects on those layers.
I set my F12 key to be my switch between parallel and perspective camera views and it's helpful.
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Very good advise...at least there is a work around, Thank you.. I do absolutely hate working in parallel projection but beggars can't be choosers... Appreciate the help!
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It really is a bummer. I hate showing my boss a model I've obviously put a lot of time into, which works great in every way... until I need to get a ground floor view (through a window, for example).
Fixing the clipping plane is obviously a hard coded fact-of-life. But I wish I could temporarily disable it when standing still...
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I'm certainly no expert on computer graphics but It seems to me that computing has reached a level of sophistication in both hardware and software to where these issues should not exist.
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@deadtaco said:
The only way to fix the clipping issue is to zoom way out and then switch to parallel projection for your camera. Now you'll be able to zoom back in without clipping. Turning off layers/hiding objects has zero effect on the clipping plane issue. The only way to fix it is to completely remove all objects on those layers.
I set my F12 key to be my switch between parallel and perspective camera views and it's helpful.
I was just having the same problem and the above fixed my issue, thank you
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