Well I am, once again, confused and frustrated, with complexity of doing simple things in Houdini.
Now its the Blast SOP. My understanding, from watching demos and tuts, that after a Blast SOP is appended to the network, I am suppoused to select faces, and press RMB. However as soon as I append Blast SOP to the network, all of geometry disappears, before I can do anything. The Blast SOP is usually appended after Edit SOP.
Whats going on? So how do I delete faces from a mesh.

Another Q? Why does ENTER key for Edit Current Operation, DOES NOT work. If I select a SOP and press ENTER, NOTHING HAPPENS, the SOP's is not able to be edited. It does not automatically enable Display and Render flag for that SOP. I have to do it manually then enable Edit Current Operation from pull down menu.

When I append PolySplit SOP, it is not automatically enabled. Actually now, no new appended SOPs are automatically enabled when they are appended. Did something get turned off by mistake?

Construction plane grid Q? First how do I turn it off in orthogonal views? The grid on/off button only works in perspective view. Second. Where do I change its color?

I have to tell you guys honestly. I am not sure at all whats going on. I am not taking to Houdini. The pop-up help and tuts are not consistent with the actual behavior of the application. I am told to do things and they are either not happening or don't work as shown.

Dave Rindner

Hi David,


Blast SOP
—————–
Hmm… I am not familiar about the situation you are facing… You wanted to blast only some specific area of the face, right? Well, I guess here are some of the possible thing to check that think I can think of:
-Make sure that you're not selecting the entire geometry by making sure that the “Select whole geometry” (A yellow cube icon located on the left side) is off.
-Make sure that the “Select Primitives” (hit “4” key - not from the number pad) is on.
-*Make sure the “Secure Selection” is off.*

Hmm… these are the only solutions I can think of… I have never ever have any problem with Blast SOP at all since the day I begin beta-testing v5.0.



Edit Current Operation
—————
It's probably the Secure Selection. Make sure that you turn off the “Secure Selection” in SOP editor. THe secure selection is located on the left side of your Viewer. I looks look like a lock button. To make sure that your “Secure Selection” is always off, go to Edit>Preferences>Tools and uncheck “SOP-Level Secure Selction On By Default”. Hit Apply. Then Accept.

Funny, I thought I mentioned something about Secure Selection long before… :?:



Contructon Plane/Ortho Grid
——————————–
For the ortho view (Front, Right, and Top view), hit “d” key to get to the Display Option. Go to Viewport tab, and uncheck “Display Ortho Grid”.

As far as changing the grid color goes, I am not sure you can do that. If it can, it probably has to do with the configuration files, which I never touched before. :?

Although I can't really change the Viewer background to any other color via the user interface, I believe you can change this via a configuration file, which again… I've never touched. However, you can change it from Light to Dark in Display Option>Color Scheme (located in the upper right).




Any chance that next time when you post your question regarding the video, can you specify which video you're looking at and the approximate time in the video that confused you? That way, I can go in and take a look and better understand what's happening.



Hope that helped.

A Big Cheer,
Alex

I don't know. I am trying to follow all these directions and tips. But as I said, the actual behavior of Houdini does not jive with what is suppoused to happen.

SELECT WHOLE is turned OFF
SECURE SELECTION is turned OFF.

Yet all of these problems are still happening. Even after restaring Houdini with fresh project.

Appending Blast SOP to Mesh or Polygon geoemtry immidieatly deletes everything, before I can select anything.

In EDIT sop. selecting a single polygon or mesh face selects all faces of gemetry, even though Select Whole is OFF.

Appending any new SOP does not make it active. Why is that?

ENTER key for Edit Current Operation simply does not work.

Pressing 4 on NumPad , for Select Primitives, does nothing. There is no change in any setting, no change in behavior. Nothing makes sence. Its like the whole app is messed up, and even though I did a fresh installation, its still the same.

I am very disappointed by its poor performance on my Windows machine, and its extreme resiliency to learn. It would be much simpler to learn if only I could follow the tuts, but Houdini's behavior is not consistent with tutorial instructions.

Dave Rindner

Hi David,

Ok, here's what I am doing. From new session of Houdini with nothing else.

Inside SOP editor, I append a Sphere SOP. I then change this to “Polygon” Afterward inside the Viewer, I hit tab and get a Blast SOP. I then select one of face on the polygon sphere and RMB to complete the Blast. THere is a hole. Everything is working as perfectly.


You mentioned that you're using “Mesh”. First of all, a Mesh in Houdini is one whole geometry like NURBS. This is the reason why you think that selecting a face did not work. Unlike Polygon, Mesh has no faces. Now, how do I know that Mesh has no faces? To the right side of your viewer, on the 7th icon down, you can turn on that to see “Primitive Number”. WHen your Sphere SOP is set to “Mesh”, you'll see only one number. And that's “0” as the initial starting number. But when you specify this to a “Polygon”. Now, you'll get a whole bunch of numbers on different faces.

Now, in order to convert this “Mesh” object to Polygon object, just append a Convert SOP. By default, this will convert to a Polygon object.


Umm…. I thought I stated “not from the number pad”…


DO NOT press 4 on the NumPad. Press the “4” up at the top of the alpha keys. The “4” that shares with the “$”. The number pads are generally reserved for use with entering numbers on teh channel field of your parameter.


I went through some of the tutorial videos - animations and modelings and VOPs. I have absolutely no problem with it whatsoever and everything stated in there was concised to the point that I think I actually got bored at the really basic video as far as I can remember…

The whole apps are working just fine and everything is working as expected. I actually have to go in to hunt for bugs to report to SideFX. :wink: (And, no, I am not a SideFX employee or ex-employee.)

Cheers,
A

Blast works for me just fine!
You just forgot to insert the primitive number in “Group” field in BlastSOP parameters!
After you selected primitive(or point, or whatever) in EditSOP, plase a BlastSOP and in it's parameters choose a Group Type accordingly to your selection. Then click on a button to the right of “Group” field and choose desired entry from a dropdown.

OK THX. I think I got handle on Blast SOP. How come the group# is not automatically assigned.

I get crashes and errors quite often in Houdini. I don't have to look hard.

Here are some examples.

In Edit SOP. Paint selection will quite often crash Houdini

Cube polygon SOP -> PolySplit SOP -> Blast (polys on one side of axis in order to prep geo for mirroring) -> PolySplit#2 SOP (QuadStrip with Close). At this point the PolySplit SOP creates extra points and edges without faces at world axis. So there are faces along edges of the polygon geometry with 0 surface area. They are impossible to delete without destroying geometry, and are not fused by Mirror SOP regardless of distance. Consequently the SubDivide SOP also has a problem with them generating visible creases across axis of symmetry.

File SOP. File SOP will only load geometry from folder that is no more then two levels deep. So it will load geometry from say ‘cProjects/Train’
but not from ‘cprojects/Train/Geometry’. This one I don't get.

Importing NURBS files.
File SOP does not load NURBS in OBJ format.

Primitive SOP. I would like to append this SOP to File SOP(that imports IGES NURBS). However any applied transformations in this SOP completely destroy geometry if is a NURBS shell or group (multiple surfaces). I model a lot in Rhino and export Alias V8 (IGES5.2) files.
What happens is that all the faces get different rotations, and do not stick together.

Convert SOP. I don't know, I have messed with this SOP now for a good time without usefull results. I want to use this SOP to tesselate imported NURBS shells. But it does such a terrible job, regardless of settings. The shared edges of NURBS faces don't get matching polygons. The result is very messy. Also it flips normals of random NURBS faces aso their associated polygons are also flipped. This is not a problem in source geometry as I always make sure of my surface directions before exporting.

So as you can see. It very very hard for me to get a handle on this app, as I am experiencing multiple problems simutaneously.

I cannot seem to be able to parent objects in OBJECTS. No matter what I try, and I cannot find the parenting procedure in PDF documentation. In MAYA I wopuld just drag objects below each other in MultiLister. Here its more complex and I cannot figure it out. I thought that PDF documentation would be PDF versions of the printed manuals, but it does not appear so.

Ideally. I would like to model in Rhino or Maya and import NURBS into Houdini, but its just not cooperating.
Maya was simple to learn in comparrison.
Overall I cannot make sence of this app. Its exremely tough to learn, and its not clicking for me.

Dave Rindner

DavidRindner
OK THX. I think I got handle on Blast SOP. How come the group# is not automatically assigned.

Are you appending SOPs in the viewport?

Either way, same result. Whether I append Blast SOP in Viewport or in Network Viewer. Generally, I append in Network Viewer.

Dave Rindner

Hi David,

Paint Selection Crashing
—————————
In Edit SOP, I tested the Paint selection on a 10k poly (43k vertices) model, no problem so far. Works in shaded and wireframe mode. I couldn't get Houdini to crash.


SubD Crease
—————-
-Did you apply Fuse SOP after Mirroring?
-Did you make sure that there are no irrelevant point (point that's just sitting on an edge by itself and are not connected to any other point to form an edge)? If you do, please use Blast SOP to delete them.


File SOP
———
I don't get it… I test the File SOP by loading a geometry that's 5 level deep. No problem whatsoever over here. Tested both .obj and .bgeo. Everything looks ok to me so far.

Can some one else please verify this as well?



Importing NURBS
———————
I am unaware that OBJ supports NURBS. As far as I can tell, when Houdini exports NURBS to obj, it gets converted into Poly. I tested Maya, and when it tries to export NURBS to an OBJ format, the OBJ files becomes a 0kb file.

I have never used Rhino before, and I have no NURBS in OBJ format to verify this…

Use IGES.


As far as dealing with importing/exporting NURBS, I think I'll have to let someone else with experience to tell you what's going on…



Convert SOP/inverted Normals.
————–
You wanted the poly edges to match up with the Isoparm, right? In Convert SOP, specify “Divisions per Span”, and set the U and V to 0. As far as having reversed normals, you will have to select each NURBS patch that will have inverted nomals and use Reverse SOP to invert them. After you inverted your NURBS patches, then you can convert it to poly.

I personally recommand working in the Network Editor here instead of the Viewer.

So what you can do is to turn on the Primitive Number (located on the right side of your viewer, the 7th icon down). Now you see all these numbers. So in Reverse SOP's “Source Group”, just enter those primitive numbers and voila. Those specific patches get inverted.

You'll probably need to flip around between the Reverse SOP's Display flag and the Convert SOP display flag to see which one is inverted correctly and which one is not.





Hmm… Odd. I came from Softimage at first, then just jump into Houdini when I know nothing about it. Back then, it was version 3. heheh. What I can do now in v5 far exceeds what I can do back in v3. From Houdini, picked up Maya no problem at all and as a matter of fact, I prefer to do majority of my work in Houdini over any other traditional package. Houdini is no more difficult to learn than any other package, in my humble opinion. I am not a technical person at all, honestly.

So, keep on truckin.

Cheers,
ALex

DavidRindner
Either way, same result. Whether I append Blast SOP in Viewport or in Network Viewer. Generally, I append in Network Viewer.

If you're appending the Blast SOP in a network editor, then you've given it no selection so it doesn't know what primitive numbers you want to blast (ie. empty group parameter).

If you're appending the Blast SOP in a viewport, then you need to pick your selection to blast before finishing with a right-click. If you picked a primitive rather than all your primitives, then you should see the picked numbers in the group parameter of the Blast SOP.

Finally, it seems that your trouble regarding the “Enter” key generally stems from modelling using the network editor. The “Enter” key is used to enter the operation inside the viewport on your display sop. If you simply model in the viewport, then it will manage the display/footprint/render flags for you resulting in no need to use the “Enter” key at all. Note that you can traverse up/down your SOP chain using the Page Up and Page Down keys and then to branch, you use shift+left click on the item in the tab menu instead of left-click on the item. The only other thing I can think of is that you're constantly hitting the Escape key or pressing the hand icon to go into the tumble operation instead of simply using the spacebar resulting in the need to go back into the operation of the display sop.