Jump to content
AutoDesSys

Match view question


Recommended Posts

Years ago I was trying to use the match view tool and it was not behaving for me. If I remember right, when I asked about it, I was asked what my photo source was. I said it was a client provided Iphone photo in which I was told "there within lies the problem" Apparently the view match was set up to work with real camera lenses and not the distorted photos we get with cell phones. 

1. Is this still a thing?

2. If so, does anyone know what the best mm/view angle lens works best for view match?

Link to comment
Share on other sites

I usually use a 50mm lens with no zoom which gives a cone of vision of about 63º. I also mark my position of the camera on a map and set the camera from there.

I also use google earth to grab an overview (or an imported location plan with features) and model in "anchors" (extruded objects) where known features are in the photo, that way I can just point the camera in the right direction, and fine adjust the angles and direction as needed.

I find match view works best when more advance existing structures are modelled but that is not always the case, although it's great for matching aerial views as a starting point.

Link to comment
Share on other sites

2 hours ago, Des said:

I usually use a 50mm lens with no zoom which gives a cone of vision of about 63º. I also mark my position of the camera on a map and set the camera from there.

I also use google earth to grab an overview (or an imported location plan with features) and model in "anchors" (extruded objects) where known features are in the photo, that way I can just point the camera in the right direction, and fine adjust the angles and direction as needed.

I find match view works best when more advance existing structures are modelled but that is not always the case, although it's great for matching aerial views as a starting point.

Thanks Des. Sounds like I'm still safe to plan on 50-55mm

 

Link to comment
Share on other sites

my investigations with the match tool are that even when the result looks correct when matched with a full frame of 35mm photograph

the resulting focal length is not correct

I have checked this many times by comparing manual placement of camera on a fixed surveyed point on the site plan and correct camera info from exif (focal length)

I have tested this with various focal  lengths 21mm - 200 all with varying results

I wouldn't rely on match view for a render that scrutinisation from government departments

 

pip

Link to comment
Share on other sites

It all depends on the lens/camera used. There are FOV (Field Of View) calculators available on line which allow you to input the sensor size etc. to get the angle.

But I prefer to align the views manually using known reference points. It's very important to set your Image Options to the same aspect ratio to the original photo. I usually make a copy of the original photo (6000x4000) and reduce it to say 2400x1600 before importing as a background image in Fz, it's quicker to load etc. and I can resize later before I go to render. Take this example below of an older project; I knew the position I took the shot and was able to draw a circle on the plan. Draw on a reference layer with known features, go to perspective view and use Edit cone of Vision to point and adjust the camera lining up the known features and plan, sometimes the spin needs adjusting as well. As a check you can see the focal comes out at 28.33mm with an angle of 64.86º. If I open the original photo and check its EXIF data the focal length is 18mm but remember that each lens used has a "multiplier" number. Mine just happens to be 1.6, so multiply the exif data focal length by 1.6 and you get 28.8 which is not far off at all considering the farther away the centre of interest there is a slight bend in the angle.

Also consider your camera height (eye level), if you have the level of the ground level great but it usually needs adjusting as well.

So going back to the Match View tool, I only use it as a starting point for some projects where I have modelled a certain amount of existing features accurately (not usually though) so I have points to snap to when lining it up. It can be hit and miss though.

CameraAngleSample.thumb.jpg.55eceb4bb31c3ec5780e1f5f59b79b19.jpgResultingRender.thumb.jpg.dcb2db09bd339e0e8cac5838c8e8a50e.jpg

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...