my camera tracking short test

I know that brick texture is lame but I wasn’t going to make it photorealistic. Just tested how it would look like.
Thanks to Andrew Price for the very good tutorial.

There is a bunch of sliding going on with your track…

huh
I see what you mean
and what is the best way to get rid of it? more tracking points to have smaller error?

what is your current error?

is where you have your geo aligning perfectly in the z axis to the tracking empties?

It’s pretty good, actually. There’s a little bit of slipping, but it’s not too obvious.

What kind of markers did you place on the floor, if any? The pattern on the floor lacks a lot of contrast so it may be difficult to track. If you didn’t use any added markers, this would be the perfect kind of shot for using them. Place them so they would be completely covered up by the hole.

Steve S

@Steve S, the floor would have more then enough contrast to be able to track off it… if you are having troubles with that sort of contrast, try trurning on the normalize option in the tracking sections.

The slipping is hidden from the camera rotations, but its still there… if you are wanting to improve, i would highly recommend trying to get a subpixel drift.

This looks like a very easy camera to solve.

doublebishop,
error is 1.16
also I didn’t really understand what this suppose to mean
“is where you have your geo aligning perfectly in the z axis to the tracking empties?”
I am relatively new to Blender and just trying different things. That video was my first (there are actually 2 but they both are on the base of same record and tracking. I followed a tutorial. Basically I highlighted markers, tracked them, solved camera motion, set floor and imported scene, added some objects and rendered.
If I found a way to use just carpet pattern that would be awesome. But I had some problems even with black markers :slight_smile:
Thank you for your advice, I will try to figure out what all that mean

Steve S, thank you
I used paper markers with black squares on them.

@alko

First up your error shouldnt be this high, try to aim at 0.3 or less

Once you have a low error… use the tools ‘floor’, ‘set origin’ and scale.

Then in the viewport, you should have empties all over the scene based on your tracking marker locations… these are the positions the top geo should be touching to not slide at all.

What problems did you have with the black markers? were you using affine / perspective for the tracking type or just loc? because theres lots of rotation going on loc will not cut it.

I used perspective and that was the only one record where I was able to track at least 8 markers from the 1st to the last frame. I don’t know what is the reason, but usually what I get is marker is either lost or sliding somewhere. I played with pattern size and search size but don’t know if I choose the best parameters.

I had empties, yea, but it looks like they slide (that was unnoticeable until I rendered this video)

Also is it possible to get such low error on the base of 10 markers?

Can you upload your blend file / raw video? i’ll take a look tomorrow if i have time

also who says you only need 10 markers…we have a tracking shot at the moment and it looks like we have about 80-90 markers…



There are 11 markers, not 10 :smiley: and I think all the problems here are only because I am too noobish :smiley:
Well, I hope to learn and understand Blender better eventually.

Thank you very much.

Ok first up
your hole… it was not at the same heights as the tracking markers… if you look in the scene i provided you can see the locators in the viewport… you had yours underneath where the edge of your hole was… which would mean that instead of the floor falling away, the hole would be sititng on the floor.

second… the tracking… you need more tracks and better quality ones… you seem to only have picked the circles in the center… this isnt the best as its very hard to pick up the correct point if there is lots of motion blur going across. look at the scene i have attached, look at how big mine are… you seem to only use LocRot aswell, which wont work for what you are trying to do, it is better to use affine / perspective, takes a bit longer but will give a better track. In future, if you are making tracking markers, it usually is better to have something which has less symmetry to it. something a little more abstract like triangles… or printing some of these out – http://www.filmmakin.com/media/catalog/product/cache/1/image/9df78eab33525d08d6e5fb8d27136e95/m/o/motiontrackingmarker_1.png or http://www.pupil-labs.com/media/img/all_markers.png

i also used keyframe selection to pick out keyframe a and b to gvie values 1 and 189., i used clean up tracks to remove tracks greater then .8 error… and i also enabled refine focal length / optical center / k1 / k2… what this allows the computer to do is refine the camera so that the lens / distortion is taken into account… with all of this i got a solve error of .21

This shot is quite easy, i think you could easily get below .1 solve error

lastly your comp network. its wrong. you have the distortion node at the start distorting your backplate… what you need to do is either undistort your backplate or distort your rendered images… you need the same distortion on both for it to sit properly. you should also be using camera motion blur not post motion blur

I havent fixed up your comp network as i coudlnt get it to render properly (not all the textures were in and i changed hte scale of everything)

Just a word, if you want people to take you more seriously, try not using the words noob…

I have uploaded my workings to here http://pasteall.org/blend/29287 . if you have any questions just let me know, i did all of this in 15 minutes.

OMG!!! Idk how it happened. That is it!! I just corrected it and almost got rid of all the slides.

second… the tracking… you need more tracks and better quality ones… you seem to only have picked the circles in the center… this isnt the best as its very hard to pick up the correct point if there is lots of motion blur going across. look at the scene i have attached, look at how big mine are… you seem to only use LocRot aswell, which wont work for what you are trying to do, it is better to use affine / perspective, takes a bit longer but will give a better track. In future, if you are making tracking markers, it usually is better to have something which has less symmetry to it. something a little more abstract like triangles… or printing some of these out – http://www.filmmakin.com/media/catalog/product/cache/1/image/9df78eab33525d08d6e5fb8d27136e95/m/o/motiontrackingmarker_1.png or http://www.pupil-labs.com/media/img/all_markers.png

I understand now. I’ll print new markers. That just wasn’t obvious and Andrew Price didn’t mention it in the tutorial.
Also I think I changed to perspective but on the left panel and now I remember it was mentioned that left panel is for new markers.

i also used keyframe selection to pick out keyframe a and b to gvie values 1 and 189., i used clean up tracks to remove tracks greater then .8 error… and i also enabled refine focal length / optical center / k1 / k2… what this allows the computer to do is refine the camera so that the lens / distortion is taken into account… with all of this i got a solve error of .21

This shot is quite easy, i think you could easily get below .1 solve error

About keyframes: It was said that I need to choose an interval where camera movements are the fastest. I just choose the whole video.
Also about optical center/k1/k2 etc: It was said that this is for advanced users and I thought it is not that important so far. I definitely need to see a tutorial or read about it.

lastly your comp network. its wrong. you have the distortion node at the start distorting your backplate… what you need to do is either undistort your backplate or distort your rendered images… you need the same distortion on both for it to sit properly. you should also be using camera motion blur not post motion blur

I havent fixed up your comp network as i coudlnt get it to render properly (not all the textures were in and i changed hte scale of everything)

I need to completely redo it. Wasn’t going to show this video at all but result was so pleasing (I mean from the point of view “OMG IT LOOKS ALMOST REAL WOW OMG I DID IT BY MYSELF OMG OMG” so I didn’t even notice any sliding and couldn’t keep myself from posting :smiley:

Just a word, if you want people to take you more seriously, try not using the words noob…

I have uploaded my workings to here http://pasteall.org/blend/29287 . if you have any questions just let me know, i did all of this in 15 minutes.

I never called noob anyone but sometimes use this word toward myself. I will not use it again. English obviously isn’t my native so sometimes I use words that may be not appropriate for the situation. Thanks for noticing.

Overall THANK YOU so much!!! I couldn’t imagine that I get so much help here. Usually animation threads are not that active and mainly people discuss either some outstanding works or when something funny is going on.

Now I am going to reread again all you have written here and completely retrack and redo all the modeling. I will upload what I have.

I have one more question so far: Is it possible to make tracking on video where place that is going to be used for some 3d object is not fully visible in the beginning. For example, I am recording like I am entering the room, showing how it looks, etc. Then I move my camera towards floor where is going to be a hole or any object. So at some moment that place will not be fully visible and object will be only be partially visible. I mean: can camera motion be solved when I start my video with one set of markers and finish it with another set of markers that wasn’t visible in the beginning of recording?

Thank you again!

Yes, so you can change existing tracking settings on the right hand side bar… just one more note, your trackers were too small aswell… there was no real variation for them to go off, have a look at the file i sent and notice how much larger they are. what i tried to do was get a corner of the piece of paper in the tracker as well as the dot…

About keyframes: It was said that I need to choose an interval where camera movements are the fastest. I just choose the whole video.
Also about optical center/k1/k2 etc: It was said that this is for advanced users and I thought it is not that important so far. I definitely need to see a tutorial or read about it.

So keyframes. This is where the tracking engine first tries to triangulate the depth of some of the tracking markers… i tend to try to use autokeyframe first and use those values… as usually it will try and pick a good parallax to compute off.

The refining process… is always important… try not to think of things for ‘advanced’ users or ‘new users’… just try and push yourself to understand how everything works together… having that barrier will keep you in the mindset that you are a new user. instead of someone who just wants to further their understanding of how the program works.

So. back to the refining process, you really should only do this once you have a decent track (less then 1 error solve)… what it will do is try increasing / decreasing the focal length to try and get a better solve… because no camera in real life is exactly what they say (say its a 50mm lens… it could actually be 51.23mm)…

what optical center means is where is the center of the lens… again leave this only to the refining process

k1/k2/k3 are distortion values, and finally leave this to the refining process again.

If, after the refining, you are getting really ridiculous values (such as the lens being super long when its a super short lens, k1/k2/k3 having a value of 100, or what not) just undo the last action and add in a few more tracking markers… because the refining failed… sometimes it screws up…

I have one more question so far: Is it possible to make tracking on video where place that is going to be used for some 3d object is not fully visible in the beginning. For example, I am recording like I am entering the room, showing how it looks, etc. Then I move my camera towards floor where is going to be a hole or any object. So at some moment that place will not be fully visible and object will be only be partially visible. I mean: can camera motion be solved when I start my video with one set of markers and finish it with another set of markers that wasn’t visible in the beginning of recording?

Yes, if you have a look at the blend file i uploaded… not all the tracking markers are on at all times… you just need to make sure you have a decent amount of active tracks on all frames… Another thing about this, you should try and have tracks last at least 5 frames, anything less isn’t worth it.

If you plan on not having your object being visible… you may want to look into masking as well.

Thank you again!

No probs, hope it helps… if you have another thread that you want feedback on, just message me, i only sometimes come into these types of threads (and then sometimes people are not looking to improve, so i dont give as detailed breakdowns)

I have completely redone it and also used BI for the first time instead of Cycles (It is difficult and some things are non trivial compare to Cycles).
Not sure if tentacle looks ok but at least the hole is not sliding. I used different record even though it is very similar to the previous one. When I made it I couldn’t track markers because I didn’t know what to do if marker is lost so began everything from the beginning :slight_smile: So I made another one and used it for a previous video.I just needed to see another camera tracking tutorial.
Next thing I should learn is how to hide markers.

Error now is 0.209 :slight_smile:

Nice work with the track man… looks solid,

The way i remove tracking markers is by grabbing a area near it, making it into a texture (and shadeless) and placing it over where the tracking marker is and blend it in (with transparencies)… usually works pretty well

If you are looking for a decent tutorial, look into track match blend… i havent done it myself but supposidly its quite good – http://www.blender3d.org/e-shop/product_info_n.php?products_id=147 overview is here – http://www.blender3d.org/e-shop/images/TrackMatchBlend_Previewsite/

The DVD is good but this is a great slipping problem before/after tutorial with files. Some great tips in here.

So thanks from me as well.

-Larry

That way to hide markers sounds genius :smiley:
Thanks!!!

Only works with a solid track!